sem2 lab1

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

double der1(double x, double h, double(*f)(double)){
    return ((*f)(x + h) - (*f)(x - h)) / (2 * h);
}

double der2(double x, double h, double(*f)(double)){
    return ((*f)(x + h) + (*f)(x - h) - 2*(*f)(x)) / (h*h);
}

double der3(double x, double h, double(*f)(double)){
    return ((*f)(x + 2 * h) - (*f)(x - 2 * h) - 2*(*f)(x + h) + 2*(*f)(x - h)) / (2 * h*h*h);
}

double der4(double x, double h, double(*f)(double)){
    return ((*f)(x + 2 * h) + (*f)(x - 2 * h) - 4*(*f)(x + h) - 4*(*f)(x - h) + 6*(*f)(x)) / (h*h*h*h);
}


int main()
{
    FILE *dest;
    double x = M_PI/4;
    dest = fopen("error data.txt", "wb");
    for(double h = 1e-017; h < 10; h *= 1.1){
        fprintf(dest, "%e\t%e\t%e\t%e\t%e\n", h,
                fabs(der1(x, h, &sin) - cos(x)),
                fabs(der2(x, h, &sin) + sin(x)),
                fabs(der3(x, h, &sin) + cos(x)),
                fabs(der4(x, h, &sin) - sin(x)));
    }
    fclose(dest);
    return 0;
}