名校
1 . 设计一个随机试验,使一个事件的概率与某个未知数有关,然后通过重复试验,以频率估计概率,即可求得未知数的近似解,这种随机试验在数学上称为随机模拟法,也称为蒙特卡洛法.比如要计算一个正方形内部不规则图形的面积,就可以利用撒豆子,计算出落在不规则图形内部和正方形内部的豆子数比近似等于不规则图形面积与正方形面积比,从而近似求出不规则图形的面积.
统计学上还有一个非常著名的蒲丰投针试验:平面上间隔
的平行线,向平行线间的平面上任意投掷一枚长为
的针
,通过多次试验可以近似求出针与任一平行线(以
为例)相交(当针的中点在平行线外不算相交)的概率.以
表示针的中点与最近一条平行线
的距离,又以
表示
与
所成夹角,如图甲,易知满足条件:
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/4363ceef-3c30-40dc-a92c-8c86f097c9f3.png?resizew=380)
由这两式可以确定平面上的一个矩形
,如图乙,在图甲中,当
满足___________ (
与
,
之间的关系)时,针与平行线相交(记为事件
).可用从试验中获得的频率去近似
,即投针
次,其中相交的次数为
,则
,历史上有一个数学家亲自做了这试验,他投掷的次数是5000,相交的次数为2550次,
,
,依据这个试验求圆周率
的近似值_________ .(精确到3位小数)
统计学上还有一个非常著名的蒲丰投针试验:平面上间隔
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4184597c94d1077842234d5f6c1d00a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a1dea20691c8c86b2806781e4419060.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6581916f5a65edfea257c804efee007e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe35c91649a5bea2518387a2b36e0c0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbba7bff7720b3aa33f29936ede7819e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/762f9b111db1b0fdb144bc94056f0fd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6d221cb1c3d27e184136b8c1aed88a5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/4363ceef-3c30-40dc-a92c-8c86f097c9f3.png?resizew=380)
由这两式可以确定平面上的一个矩形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cb9ad1e34877b0db02d0219332b0f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6581916f5a65edfea257c804efee007e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27b6f8cb2faaad82b53b2a66ee817a37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cf35d45fb2da96b3418768b8672c796.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/560729ce6adf77a93dad5dad9811fb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbd2d2447503cc0bc427c5d969018edd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86ebba6ed1add0fe647c0226614b9290.png)
您最近一年使用:0次