Given the value of n, find the sum of the series (2 / 3) – (4 / 5) + (6 / 7) – (8 / 9) + – – – – – – – upto n terms.
Examples :
Input : n = 5 Output : 0.744012 Series : (2 / 3) - (4 / 5) + (6 / 7) - (8 / 9) + (10 / 11) Input : n = 7 Output : 0.754268 Series : (2 / 3) - (4 / 5) + (6 / 7) - (8 / 9) + (10 / 11) - (12 / 13) + (14 / 15)
C++
// C++ program to find // sum of given series #include <bits/stdc++.h> using namespace std;
// Function to find sum of series // up-to n terms double seriesSum( int n)
{ // initializing counter by 1
int i = 1;
// variable to calculate result
double res = 0.0;
bool sign = true ;
// while loop until nth term
// is not reached
while (n > 0)
{
n--;
// boolean type variable
// for checking validation
if (sign) {
sign = !sign;
res = res + ( double )++i / ++i;
}
else {
sign = !sign;
res = res - ( double )++i / ++i;
}
}
return res;
} // Driver Code int main()
{ int n = 5;
cout << seriesSum(n);
return 0;
} |
Java
// Java program to find // sum of given series import java.io.*;
class GFG {
// Function to find sum of series
// up-to n terms
static double seriesSum( int n)
{
// initializing counter by 1
int i = 1 ;
// variable to calculate result
double res = 0.0 ;
boolean sign = true ;
// while loop until nth term
// is not reached
while (n > 0 )
{
n--;
// boolean type variable
// for checking validation
if (sign)
{
sign = !sign;
res = res + ( double )++i / ++i;
}
else {
sign = !sign;
res = res - ( double )++i / ++i;
}
}
return res;
} // Driver Code
public static void main (String[] args) {
int n = 5 ;
System.out.print(seriesSum(n));
}
} // This code is contributed by vt_m |
Python3
# Python3 program to find # sum of given series # Function to find # sum of series # up-to n terms def seriesSum(n):
# initializing
# counter by 1
i = 1 ;
# variable to
# calculate result
res = 0.0 ;
sign = True ;
# while loop until nth
# term is not reached
while (n > 0 ):
n = n - 1 ;
# boolean type variable
# for checking validation
if (sign):
sign = False ;
res = res + (i + 1 ) / (i + 2 );
i = i + 2 ;
else :
sign = True ;
res = res - (i + 1 ) / (i + 2 );
i = i + 2 ;
return res;
# Driver Code n = 5 ;
print ( round (seriesSum(n), 6 ));
# This code is contributed # by mits |
C#
// C# program to find // sum of given series using System;
class GFG {
// Function to find sum of
// series up-to n terms
static double seriesSum( int n)
{
// initializing counter by 1
int i = 1;
// variable to calculate result
double res = 0.0;
bool sign = true ;
// while loop until nth term
// is not reached
while (n > 0)
{
n--;
// boolean type variable
// for checking validation
if (sign)
{
sign = !sign;
res = res + ( double )++i / ++i;
}
else
{
sign = !sign;
res = res - ( double )++i / ++i;
}
}
return res;
} // Driver Code
public static void Main () {
int n = 5;
Console.Write(seriesSum(n));
}
} // This code is contributed by vt_m |
PHP
<?php // PHP program to find // sum of given series // Function to find sum of series // up-to n terms function seriesSum( $n )
{ // initializing counter by 1
$i = 1;
// variable to calculate result
$res = 0.0;
$sign = true;
// while loop until nth term
// is not reached
while ( $n > 0)
{
$n --;
// boolean type variable
// for checking validation
if ( $sign ) {
$sign = ! $sign ;
$res = $res + (double)++ $i / ++ $i ;
}
else {
$sign = ! $sign ;
$res = $res - (double)++ $i / ++ $i ;
}
}
return $res ;
} // Driver Code $n = 5;
echo (seriesSum( $n ));
// This code is contributed by Ajit. ?> |
Javascript
<script> // javascript program to find // sum of given series // Function to find sum of series // up-to n terms function seriesSum( n)
{ // initializing counter by 1
let i = 1;
// variable to calculate result
let res = 0.0;
let sign = true ;
// while loop until nth term
// is not reached
while (n > 0)
{
n--;
// boolean type variable
// for checking validation
if (sign) {
sign = !sign;
res = res + ++i / ++i;
}
else {
sign = !sign;
res = res - ++i / ++i;
}
}
return res;
} // Driver Code let n = 5 ; document.write(seriesSum(n).toFixed(6)) ;
// This code contributed by aashish1995 </script> |
Output :
0.744012
Time Complexity: O(n), where n represents the given integer.
Auxiliary Space: O(1), no extra space is required, so it is a constant.