#include <stdio.h>
#include <math.h>

int main(void)
{
    int n;
    double j;
    double Xobsh = 0;
    double Yobsh = 0;
    double XYobsh = 0;
    double X_v_kvobsh = 0;
    double Y_v_kvobsh = 0;
    double x;
    double y;
    double k;
    double b;
    double Pogreshnos_k;
    double Pogreshnos_B;
    double pi;

    n = 1000;
    pi = M_PI;
    for (j = 0; j <= pi / 2.0; j += pi / n / 2.0)
    {
        x = j;
        y = sin(x);
        Xobsh += x;
        Yobsh += y;
        XYobsh += x*y;
        X_v_kvobsh += x*x;
        Y_v_kvobsh += y*y;
    }
    Xobsh /= n;
    Yobsh /= n;
    XYobsh /= n;
    X_v_kvobsh /= n;
    Y_v_kvobsh /= n;
    k = (XYobsh - Xobsh * Yobsh) / (X_v_kvobsh - Xobsh * Xobsh);
    Pogreshnos_k = sqrt((Y_v_kvobsh - Yobsh*Yobsh) / (X_v_kvobsh - Xobsh * Xobsh) - k * k) / sqrt(n);
    b = Yobsh - k * Xobsh;
    Pogreshnos_B = Pogreshnos_k * sqrt(X_v_kvobsh - Xobsh * Xobsh);
    printf("\nIf plot is type y = kx + b\n");
    printf("k = %lg, b = %lg\n", k, b);
    printf("Error of k = %lg, Error of b = %lg\n", Pogreshnos_k, Pogreshnos_B);
    return 0;
}