The value of π can be determined by the series equation

π=4∗(1-1/3+1/5−1/7+1/9−1/11+1/13…)

Write a program that prompts the user to enter a positive odd number n and uses recursion to approximate the value of π using the given formula including term up through 1/n.

Solution:

#include <iostream>

#include <cmath>

using namespace std;

double pi (double);

int main()

{

cout << "Enter n to value of pi: "; int n; cin>>n;

cout << pi(n) << endl;

return 0;

}

double pi (double n)

{

if (n==1)

return 4*1;

else

return ( 4*(pow(-1,n+1)*(1/(2*n-1))) + pi(n-1) );

}

π=4∗(1-1/3+1/5−1/7+1/9−1/11+1/13…)

Write a program that prompts the user to enter a positive odd number n and uses recursion to approximate the value of π using the given formula including term up through 1/n.

Solution:

#include <iostream>

#include <cmath>

using namespace std;

double pi (double);

int main()

{

cout << "Enter n to value of pi: "; int n; cin>>n;

cout << pi(n) << endl;

return 0;

}

double pi (double n)

{

if (n==1)

return 4*1;

else

return ( 4*(pow(-1,n+1)*(1/(2*n-1))) + pi(n-1) );

}