trap

#include<iostream>
#include<math.h>
double func(double x)
{
    double arg = 0;
    arg = 1 / (1 + pow(x, 3));
    return arg;
}
double trap(double node)
{

    double sum = 0;
    double a = 0;
    double b = 1;
    for (int i = 0; i < node; i++)
    {
        sum = sum + (((b - a) /(2*node))*((func(a/node) + func(b / node))));
        a = a++;
        b = b++;
    }
    return sum;
}
void main()
{
    double sum = 0;
    sum = trap(50);
    std::cout.precision(8);
    std::cout << sum;
    getchar();
}