#include <stdio.h>
#include <stdlib.h>
#include <math.h>
float funcos(float e, float x);
int main()
{
float e,x,sum;
printf("input e : ");
scanf("%f",&e);
printf("\n");
printf("input x: ");
scanf("%f",&x);
printf("\n");
sum = funcos(e,x) ;
printf("sum = %f\n",sum);
return 0;
}
float funcos(float e, float x)
{
float result=1 ,mole=1,deno=1,value = 1;
int i,j;
j = -1 ;
for(i = 2 ;value>e; i+=2)
{
mole = mole*x*x; ;
deno = deno * i*(i-1) ;
value = mole/deno ;
result = result + j*mole/deno ;
j = -j ;
}
return result ;
}