color:rgb(51,51,51); font-family:Georgia,serif; font-size:15px; line-height:27px"> class="tags" href="/tags/BianCheng.html" title=编程>编程之美最后一题“挖雷class="tags" href="/tags/YouXi.html" title=游戏>游戏的概率”没附答案, 有一则脚注云“此题适合MATLAB用户解答”, 颇感有趣. 题目说, 一局16×16的扫雷class="tags" href="/tags/YouXi.html" title=游戏>游戏刚开始, 只翻开了两格, 分别显示数字1和2, 如下图所示(只画出了3×5的局部示意图). 设地雷总数从10逐渐增加到240, 请分别作出图中A, B, C三处为地雷的概率曲线.

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color:rgb(51,51,51); font-family:Georgia,serif; font-size:15px; line-height:27px"> 此题适合用MATLAB解答是因为要求作出概率曲线. 如果地雷总数一定, 其实手算也很容易. 根据数字1和2的提示, 图示3×5方格中至少2个地雷, 至多3个地雷. 记class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-8" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; 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overflow-x:hidden; overflow-y:hidden; width:0px; height:0.685em"> 为扫雷class="tags" href="/tags/YouXi.html" title=游戏>游戏中格子总数, class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-17" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:0.825em">color:initial; vertical-align:0px; top:-2.237em; left:0em">class="mrow" id="MathJax-Span-18" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-19" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-style:italic">Nck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:0em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:0.663em"> 为地雷总数. 分两种情况考虑.

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border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-60" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)class="mo" id="MathJax-Span-61" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="texatom" id="MathJax-Span-62" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-63" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-64" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-65" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-66" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:0.412em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mn" id="MathJax-Span-67" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">5ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mn" id="MathJax-Span-68" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">1ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-69" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:3.268em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.631em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:1.746em"> .
   • A处为地雷的情况总数: class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-70" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:0.55em">color:initial; vertical-align:0px; top:-2.237em; left:0em">class="mrow" id="MathJax-Span-71" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mn" id="MathJax-Span-72" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">0ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.021em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:0.667em"> .
   • B处为地雷的情况总数: class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-73" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:7.079em">color:initial; vertical-align:0px; top:-3.268em; left:0em">class="mrow" id="MathJax-Span-74" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="texatom" id="MathJax-Span-75" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-76" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-77" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-78" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-79" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:2.268em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mrow" id="MathJax-Span-80" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-81" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Mclass="mo" id="MathJax-Span-82" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-83" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">15ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mrow" id="MathJax-Span-84" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-85" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Nclass="mo" id="MathJax-Span-86" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-87" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">2ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-88" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)class="mo" id="MathJax-Span-89" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="mn" id="MathJax-Span-90" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">1class="mo" id="MathJax-Span-91" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="texatom" id="MathJax-Span-92" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-93" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-94" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-95" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-96" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:0.412em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mn" id="MathJax-Span-97" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">5ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mn" id="MathJax-Span-98" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">1ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-99" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:3.268em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.631em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:1.746em"> .
   • C处为地雷的情况总数: class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-100" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:7.079em">color:initial; vertical-align:0px; top:-3.268em; left:0em">class="mrow" id="MathJax-Span-101" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="texatom" id="MathJax-Span-102" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-103" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-104" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-105" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-106" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:2.268em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mrow" id="MathJax-Span-107" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-108" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Mclass="mo" id="MathJax-Span-109" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-110" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">15ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mrow" id="MathJax-Span-111" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-112" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Nclass="mo" id="MathJax-Span-113" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-114" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">2ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-115" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)class="mo" id="MathJax-Span-116" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="texatom" id="MathJax-Span-117" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-118" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-119" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-120" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-121" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:0.412em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mn" id="MathJax-Span-122" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">3ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mn" id="MathJax-Span-123" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">1ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-124" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)class="mo" id="MathJax-Span-125" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="mn" id="MathJax-Span-126" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">1ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:3.268em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.631em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:1.746em"> .
2. 图中共3个地雷时可能的情况总数: class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-127" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:8.179em">color:initial; vertical-align:0px; top:-3.268em; left:0em">class="mrow" id="MathJax-Span-128" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="texatom" id="MathJax-Span-129" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-130" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-131" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-132" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; 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   • A处为地雷的情况总数: class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-161" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; 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padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-169" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Mclass="mo" id="MathJax-Span-170" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-171" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">15ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mrow" id="MathJax-Span-172" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-173" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Nclass="mo" id="MathJax-Span-174" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-175" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">3ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-176" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)class="mo" id="MathJax-Span-177" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="mn" id="MathJax-Span-178" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">1class="mo" id="MathJax-Span-179" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="texatom" id="MathJax-Span-180" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-181" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-182" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-183" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-184" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:0.412em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mn" id="MathJax-Span-185" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">5ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mn" id="MathJax-Span-186" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">2ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-187" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:3.268em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.631em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:1.746em"> .
   • B处为地雷的情况总数: class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-188" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:0.55em">color:initial; vertical-align:0px; top:-2.237em; left:0em">class="mrow" id="MathJax-Span-189" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mn" id="MathJax-Span-190" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">0ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.021em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:0.667em"> .
   • C处为地雷的情况总数: class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-191" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:8.179em">color:initial; vertical-align:0px; top:-3.268em; left:0em">class="mrow" id="MathJax-Span-192" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="texatom" id="MathJax-Span-193" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-194" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-195" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-196" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-197" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:2.268em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mrow" id="MathJax-Span-198" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-199" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Mclass="mo" id="MathJax-Span-200" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-201" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">15ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mrow" id="MathJax-Span-202" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-203" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Nclass="mo" id="MathJax-Span-204" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-205" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">3ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-206" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)class="mo" id="MathJax-Span-207" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="texatom" id="MathJax-Span-208" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-209" style="margin-top:0px; margin-right:0px; margin-bottom:0px; 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vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-212" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:0.412em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mn" id="MathJax-Span-213" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">5ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mn" id="MathJax-Span-214" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">1ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-215" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)class="mo" id="MathJax-Span-216" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main">⋅class="texatom" id="MathJax-Span-217" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0.222em; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-218" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-219" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-220" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-221" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:0.412em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mn" id="MathJax-Span-222" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">4ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mn" id="MathJax-Span-223" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">1ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-224" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:3.268em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.631em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:1.746em"> .

color:rgb(51,51,51); font-family:Georgia,serif; font-size:15px; line-height:27px"> 要求的概率可以简单地相除得到:

color:rgb(51,51,51); font-family:Georgia,serif; font-size:15px; line-height:27px"> 注意到所求的是比值, 所以class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial"> class="math" id="MathJax-Span-433" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; height:0px; width:3.505em">color:initial; vertical-align:0px; top:-3.268em; left:0em">class="mrow" id="MathJax-Span-434" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="texatom" id="MathJax-Span-435" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mrow" id="MathJax-Span-436" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mfenced" id="MathJax-Span-437" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mo" id="MathJax-Span-438" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">(class="mfrac" id="MathJax-Span-439" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">ck; position:relative; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; height:0px; width:2.268em">color:initial; vertical-align:0px; top:-2.681em; left:50%">class="mrow" id="MathJax-Span-440" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-441" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Mclass="mo" id="MathJax-Span-442" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-443" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">15ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">color:initial; vertical-align:0px; top:-1.892em; left:50%">class="mrow" id="MathJax-Span-444" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px">class="mi" id="MathJax-Span-445" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Nclass="mo" id="MathJax-Span-446" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-447" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">2ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-448" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:3.268em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.631em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:1.746em"> 和class="MathJax" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; font-family:serif; line-height:normal; text-align:left; word-spacing:normal; word-wrap:normal; white-space:nowrap; float:none; direction:ltr; 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border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Math; font-size:12px; font-style:italic">Nclass="mo" id="MathJax-Span-462" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">−class="mn" id="MathJax-Span-463" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Main; font-size:12px">3ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:2.237em">class="mo" id="MathJax-Span-464" style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; display:inline; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:-0.001em">c; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; font-family:MathJax_Size2">)ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0px; border-style:initial; border-color:initial; vertical-align:0px; width:0px; height:3.268em">ck; position:static; border-top-width:0px; border-right-width:0px; border-bottom-width:0px; border-left-width:0em; border-style:initial; border-color:initial; vertical-align:-0.631em; font-family:MathJax_Main,MathJax_Size1,MathJax_AMS; border-left-style:solid; border-left-color:initial; overflow-x:hidden; overflow-y:hidden; width:0px; height:1.746em"> 的值并不重要, 只需知道二者之比. 可以利用

color:rgb(51,51,51); font-family:Georgia,serif; font-size:15px; line-height:27px"> MATLAB程序很简单, 就不贴了. 最后附上曲线图.
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