14.Trapizoidal rule:

 

14.Trapizoidal rule:

by ujjal roy

//dy/dx=x+y;

#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;

    sum=f(lower);

    sum+=f(upper);

    sum/=2;

    x=lower+h;

   for(int i=1;i<subdivide;i++)

   {

       sum+=f(x);

       x+=h;

   }

  sum*=h;

  cout<<sum<<endl;

    return 0;

}