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

 double hordi(double x1, double x2, double epsilon){
    double x, x3, fx1, fx2, f, k, b;
    x3=2000;
    do
    {
        fx1 = sin(x1) - 0.5;
        fx2 = sin(x2) - 0.5;
        if (fx1 * fx2 > 0)
            return -1;
        x=x3;
        k = (fx2 - fx1) / (x2 - x1);     /* Nahodim koafficient k */
        b = fx1 - (((fx2 - fx1) * x1) / (x2 - x1));  	/* Nahodim svobodnii chlen b */
        x3 = x1 - (((x2-x1) * fx1)/(fx2-fx1));  /* Nahodim tochku persechenia */
        f = sin(x3) - 0.5;

        if (f * fx1 > 0)
	x1 = x3;
        else
              x2 = x3;
    }
    while (fabs(x3-x) > epsilon);
    return x3;
}
int main(void)
{
    double otvet;
    otvet = hordi(0, 2, 1e-6);
    if (otvet == -1)
        printf("nepravilnij interval");
    else
    {	printf("%f", otvet);
	printf("/n");
    }

    return 0;
}