15.Simpson’s 1/3 rule:

 

15.Simpson’s 1/3 rule:

by ujjal roy

//dy/dx=1/(x*x);

#include<bits/stdc++.h>

using namespace std;

double f(double x)

{

    return 1.0/(1+x*x);

}

int main()

{

    double upper,lower,subdivide,x;

    cout<<"Enter upper limit , lower limit and subdivide  : ";

    cin>>upper>>lower>>subdivide;

    double h;

    h=(upper-lower)/subdivide;

    double sum,sum1=0,sum2=0;

    sum=f(lower);

    sum+=f(upper);

    x=lower+h;

   for(int i=1;i<subdivide;i++)

   {

       double r;

       r=f(x);

       if(i%2==0)sum2+=r;

       else sum1+=r;

       x+=h;

   }

   

   sum+=(4*sum1+2*sum2);

  sum*=h;

  sum/=3;

  cout<<sum<<endl;

    return 0;

}