programiranje u c-u --- POMOC

[rastaman252]

#include <stdio.h>
void main(){
int n;
float var;
float rez=1;
printf("Unesi n: ");
scanf("%d", &n);
for(x=1;x<n;x++){
var=((2*x)*(2*x))/((2*x-1)*(2*x+1));
rez*=var;}
printf("Aproskimirani PI/2 je: %f", rez);
}