#include <stdio.h>

main() {
	float x, num, sum;
	int n, i, j, den;

	printf("Cos(x). Intro \"x n\": ");
	scanf("%f %d", &x, &n);

	for(i=0, sum=0; i<=n; i++) {
		for(j=1, num=1, den=1; j<=2*i; j++) {
			num = num*x;
			den = den*j;
		}
		if (i%2==0) {
			sum = sum + num/den;
		} else {
			sum = sum - num/den;
		}
		printf("i=%d\tsum=%f\tnum=%f\tden=%d\n", i, sum, num, den);
	}

	printf("Cos(%f) = %f\n", x, sum);
}