Newton - Raphson Method

#include <stdio.h>
#include <math.h>
double f(double a){return 0.7-a+sin(a);}
double fturev(double a){return -1+cos(a);}

int main()
{
    double epsilon,x1,fark,x2;
    printf("X1 : "); scanf("%lf",&x1);
    printf("epsilon : "); scanf("%lf",&epsilon);

    do{
        x2 =  x1 - (f(x1)  / fturev(x1)) ;
        fark = fabs(x1-x2);
        printf("x1 = %.15lf , x2 = %.15lf , fark = %.15lf \n",x1,x2,fark );
        if( fark > epsilon ) { x1 = x2;}
    } while( fark > epsilon );

    return 0;
}