Do not pour out HDU - 5954 数学积分

题目：题目链接

思路：纯高等数学问题，不过不是很好积分，具体积分思路及过程参考大佬博客——https://blog.csdn.net/danliwoo/article/details/53002695

AC代码：

 #include <iostream>
 #include <cstdio>
 #include <algorithm>
 #include <cmath>
 #include <iomanip>

 using namespace std;

 #define pi acos(-1.0)

 double h;

 double cal(double a) {
     return pi * cos(a) - a * cos(a) + sin(a) - pow(sin(a), ) / ;
 }

 double calV(double b) {
     double a = acos( * tan(b) - 1.0);
     return (cal(a) - cal(pi)) / tan(b);
 }

 int main()
 {
     int T;
     scanf("%d", &T);
     while(T--) {
         scanf("%lf", &h);
         double v = pi * h;
         if(h < 1e-)
             printf("0.00000\n");
         else if(h >= 1.0) {
             double a = atan(2.0 - h);
             printf("%.5f\n", pi / cos(a));
         }
         else {
             double l = , r = pi / ;
             while(r - l > 1e-) {
                 double m = (l + r) / ;
                 if(calV(m) < v)
                     l = m;
                 else
                     r = m;
             }
             double x =  * tan(r);
             double a = acos(x - );
             double s = (pi - a + sin(a) * cos(a)) / sin(r);
             printf("%.5f\n", s);
         }
     }
     return ;
 }