Can you solve this equation?

最新推荐文章于 2019-05-01 22:18:17 发布

原创最新推荐文章于 2019-05-01 22:18:17 发布 · 344 阅读

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本文介绍了一种使用二分法求解特定多项式方程在0到100区间内的实数根的方法，并提供了完整的C++代码实现。该算法能够准确地找到方程的解或判断在指定范围内是否存在解。

Now,given the equation 8*x^4 + 7*x^3 + 2*x^2 + 3*x + 6 == Y,can you find its solution between 0 and 100;
Now please try your lucky.

Input

The first line of the input contains an integer T(1<=T<=100) which means the number of test cases. Then T lines follow, each line has a real number Y (fabs(Y) <= 1e10);

Output

For each test case, you should just output one real number(accurate up to 4 decimal places),which is the solution of the equation,or “No solution!”,if there is no solution for the equation between 0 and 100.

Sample Input

2
100
-4

Sample Output

1.6152
No solution!

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
double l,h,mid,y;
double run(double x)
{
    return 8*pow(x,4)+7*pow(x,3)+2*pow(x,2)+3*x+6;
}
int main()
{
    int T;
    cin>>T;
    while(T--)
    {
        cin>>y;
        l=0;h=100;
        while(l+1e-8<h)
        {
            mid=(l+h)/2;
            if(run(mid)>y) h=mid;
            else l=mid;
        }
        if (l==0||h==100) cout<<"No solution!"<<endl;
        else printf("%.4lf\n",l);
    }
    return 0;
}