#include <iostream>
#include <cmath>

using namespace std;

int main() {
    double a = 0.0;
    double b = 1.57;
    int n = 10;

    double dx = (b - a) / n;
    double s = 0.0;

    for (int i = 0; i < n; i++) {
        double x = a + (i + 0.5) * dx; // środek prostokąta
        s += dx * sin(x);
    }

    cout << "Przyblizona wartosc pola (metoda prostokatow) = " << s << endl;

    return 0;
}