please identify the mistake in the given coding

Write a function to find value of sin(x) using Expansion Series given below:

Code:

sin(x) = x - x^3/3! + x^5/5! - x^7/7!......

answer-
#include <stdio.h>
#include <math.h>
 int factorial(int a) {
 	int i,k;
 	for(i=a;i>0;i--) {
	 	k=k*i;
	 }
	 return k;
 }
 
 float power(float a,float b) {
 	float i,j;
 	j=1;
 	for(i=1;i<=b;i++)  {
	 	j=j*a;
	 }
	 return j;
 }
 
 int main()  {
 	float i,x,y,term,sum=0;
 	printf("Enter the variable x\n");
 	printf("Enter the prescribed precision\n");
 	scanf("%f%f",&x,&y);
 	for(i=1;(term/sum)*100<=y;i++) {
	 	term=power(-1,(i+1))*power(x,(2*i-1))/factorial((2*i-1));
	 	sum+=term;
	 }
	 printf("sin(%f)=%f",x,sum);
	 return 0;
 }

 

In for(i=1;(term/sum)*100<=y;i++) you have done like(term/sum) which is 0/0 which is not valid mathematical operation.

 

And why are you dividing it and comparing it with "y"?

 

(Term/sum) is the precision term which is compared with 'y' (here y is the max tolerable error)