write a program to integrate a function using Gauss's Quadrature Formula in c++.

CODE:

#include<iostream.h>

#include<conio.h>

#include<iomanip.h>

float g(float y)

{ return(y*y)+(8.0*y)+15;

}

void main()

{

clrscr();

int i,n;

float r[10],y[10],sum,a,b,integral;

cout<<"enter the value of n for no. of point=";

cin>>n;

cout<<"enter the first interval a =";

cin>>a;

cout<<"enter the second interval b=";

cin>>b;

for(i=1;i<=n;i++)

{

cout<<"enter the value of R["<<"]=";

cin>>r[i];

cout<<"enter the value of y["<<"]=";

cin>>y[i];

}

sum=0;

for(i=1;i<=n;i++)

{sum=sum+(r[i]*g(y[i]));

}

integral=((b-a)/2.0)*sum;

cout.setf(ios::showpoint);

cout<<setprecision(4);

cout<<"vale of the integral="<<integral;

getch();

}

OUTPUT:

How To