#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 += F(x);
else
switch( i%6 )
{
case 1: y += 5.0 * F(x); break;
case 2: y += 1.0 * F(x); break;
case 3: y += 6.0 * F(x); break;
case 4: y += 1.0 * F(x); break;
case 5: y += 5.0 * F(x); break;
case 0: y += 2.0 * F(x); break;
}
}
y *= 3.0 * h / 10.0;
printf("\n Value of integration = %.10f", y );
getch();
}
Output