task2

#include <iostream>
#include <math.h>

using namespace std;

double fun(double x);
double integral(double start, double end, double epsil, double (*f) (double));

int main()
{
    cout << "Please, enter start and end: ";
    double a, b, epsil, result;
    cin >> a >> b;
    cout << "Please, enter epsil: ";
    cin >> epsil;
    result = integral(a, b, epsil, fun);
    cout << "Integral = " << result << endl;
    return 0;
}

double fun(double x)
{
    return sin(x)/(1+pow(x, 2));
}

double integral(double start, double end, double epsil, double (*f) (double))
{
    double s = 0;
    for (double x = start; x<end; x+=epsil)
        s += fabs(f(x)+f(x+epsil))/2;
    return s*epsil;
}