Solve the equation:
p ∗ e −x + q ∗ sin(x) + r ∗ cos(x) + s ∗ tan(x) + t ∗ x 2 + u = 0
where 0 ≤ x ≤ 1.
Input
Input consists of multiple test cases and terminated by an EOF. Each test case consists of 6 integers in a single line: p, q, r, s, t and u (where 0 ≤ p, r ≤ 20 and −20 ≤ q, s, t ≤ 0). There will be maximum 2100 lines in the input file.
Output
For each set of input, there should be a line containing the value of x, correct up to 4 decimal places, or the string ‘No solution’, whichever is applicable.
Sample Input
0 0 0 0 -2 1
1 0 0 0 -1 2
1 -1 1 -1 -1 1
Sample Output
0.7071
No solution
0.7554
题意：给出一个方程，求解X;
思路：因为方程是单调递减的，所以二分求解；
#include<iostream>
#include<cstdio>
#include<cmath>
#define EPS (10e-8)
using namespace std;
double p,q,r,s,t,u;
inline double fomula(double x){
return p*exp(-x)+q*sin(x)+r*cos(x)+s*tan(x)+t*x*x+u;
}
int main(){
while(scanf("%lf%lf%lf%lf%lf%lf",&p,&q,&r,&s,&t,&u)!=EOF){
double left=, right=, mid;
bool flag=false;
if(fomula(left)*fomula(right) > ){
printf("No solution\n");
continue;
}
while(right-left > EPS){
mid = (left+right)/;
if(fomula(mid)*fomula(left) > ) left=mid;
else right=mid;
} printf("%.4f\n", mid);
}
return ;
}