UVa 10341 (二分求根) Solve It

很水的一道题，因为你发现这个函数是单调递减的，所以二分法求出函数的根即可。

 #include <cstdio>
 #include <cmath>
 //using namespace std;

 const double e = 1e-;
 double p, q, r, s, t, u;

 inline double f(double x)
 { return p*exp(-x) + q*sin(x) + r*cos(x) + s*tan(x) + t*x*x + u; }

 int main()
 {
     //freopen("in.txt", "r", stdin);

     while(scanf("%lf%lf%lf%lf%lf%lf", &p, &q, &r, &s, &t, &u) == )
     {
         if(f()<-e || f()>e) { puts("No solution"); continue; }
         double L = , R = , m;
         for(int i = ; i < ; i++)
         {
             m = (L+R)/;
             if(f(m) < ) R = m;
             else L = m;
         }
         printf("%.4f\n", m);
     }

     return ;
 }

代码君