方法简析
简单地说，当我们找不到问题的确切解时，我们可以进行随机抽样，根据统计检验找到问题的近似解。
[En]
To put it simply, when we are unable to find the exact solution of a problem, we can carry out random sampling and find the approximate solution of the problem according to the statistical test.
(\pi) 的近似求解
已知：圆的面积 (S(r)=\pi r^2)（别问我为什么），于是
[ \pi = S(1) ]
构造单位圆的外接正方形，如下图
首先将点随机分布到正方形中(均匀分布)。当点数达到一定程度时，从统计分析的角度来看，必然存在
[En]
First randomly distribute points into the square (uniform distribution). When the number of points reaches a certain degree, from the point of view of statistical analysis, there must be
[ \frac{S_{圆}}{S_{正方形}} \approx \frac{圆内点的个数}{正方形内点的总数量} ]
因此
[ \pi = S(1) \approx 4\times\frac{圆内点的个数}{正方形内点的总数量} ]