UVA11646

题意:
给定一个圆弧边矩形，长a宽b，周长为400，且两边的圆弧同属一个圆。给出长宽比m：n，求长和宽



策略：列方程求解。
令k=n/m,则解出a = 200 / (1 + atan(k)*sqrt(1+k*k));

代码：

#include <iostream>#include <stdio.h>using namespace std;int main(){//    freopen("in.txt", "r", stdin);    int m, n;    int id = 1;    while(scanf("%d : %d", &m, &n)!=EOF){        double k = n*1.0/m;        double a = 200/(1+atan(k)*sqrt(1+k*k));        double b = a*k;        printf("Case %d: %.10lf %.10lf\n", id++, a, b);    }    return 0;}