#include <stdio.h>
#include <conio.h>
#include <math.h>
#define F(x) (1.0/(1.0+x*x))
main()
{
int i, n;
double a, b, h, x, y = 0.0;
printf(" Enter lower limit : ");
scanf("%lf", &a);
printf(" Enter upper limit : ");
scanf("%lf", &b);
printf(" Enter number of subintervals : ");
scanf("%d", &n);
h = (b - a) / (double)(n);
for( i=0, x=a; i<=n ; i++, x+=h)
{
if( i == 0 || i == n )
y += 7.0 * F(x);
else
if( i%4 == 1 || i%4 == 3 )
y += 32.0 * F(x);
else
if( i%4 == 2 )
y += 12.0 * F(x);
else
y += 14.0 * F(x);
}
y *= 2.0 * h / 45.0;
printf("\n Value of integration = %.10f", y );
getch();
}
Output