编程求∫(sin2x/x)dx

#include "stdio.h"
#include "math.h"
#define d 10 /*我不知道d是常量还是变量,我这里就当常量了啊*/
void main()
{
double s;
int x;
printf("inpu x:");
scanf("%d",&x);
s=(sin(2*x)/(double)x)*d*x;
printf("result is %d\n",s);
}