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Program to find the sum of the series 1 + x + x^2+ x^3+ .. + x^n
• Last Updated : 06 Jun, 2021

Given an integer X, the task is to print the series and find the sum of the series Examples :

Input: X = 2, N = 5
Output: Sum = 31
1 2 4 8 16
Input: X = 1, N = 10
Output: Sum = 10
1 1 1 1 1 1 1 1 1 1

Approach: The idea is to traverse over the series and compute the sum of the N terms of the series. The Nth term of the series can be computed as:

Nth Term = (N-1)th Term * X

Below is the implementation of the above approach:

## C++

 `// C++ implementation to find``// sum of series of``// 1 + x^2 + x^3 + ....+ x^n` `#include ` `using` `namespace` `std;` `// Function to find the sum of``// the series and print N terms``// of the given series``double` `sum(``int` `x, ``int` `n)``{``    ``double` `i, total = 1.0, multi = x;` `    ``// First Term``    ``cout << total << ``" "``;` `    ``// Loop to print the N terms``    ``// of the series and find their sum``    ``for` `(i = 1; i < n; i++) {` `        ``total = total + multi;``        ``cout << multi << ``" "``;``        ``multi = multi * x;``    ``}` `    ``cout << ``"\n"``;``    ``return` `total;``}` `// Driver code``int` `main()``{``    ``int` `x = 2;``    ``int` `n = 5;``    ``cout << fixed``         ``<< setprecision(2)``         ``<< sum(x, n);``    ``return` `0;``}`

## C

 `// C implementation to find the sum``// of series 1 + x^2 + x^3 + ....+ x^n` `#include ``#include ` `// Function to print the sum``// of the series``double` `sum(``int` `x, ``int` `n)``{``    ``double` `i, total = 1.0, multi = x;` `    ``// First Term of series``    ``printf``(``"1 "``);` `    ``// Loop to find the N``    ``// terms of the series``    ``for` `(i = 1; i < n; i++) {` `        ``total = total + multi;``        ``printf``(``"%.1f "``, multi);``        ``multi = multi * x;``    ``}``    ``printf``(``"\n"``);``    ``return` `total;``}` `// Driver Code``int` `main()``{``    ``int` `x = 2;``    ``int` `n = 5;``    ``printf``(``"%.2f"``, sum(x, n));``    ``return` `0;``}`

## Java

 `// Java implementation to find``// the sum of series``// 1 + x^2 + x^3 + ....+ x^n` `class` `GFG {` `    ``// Java code to print the sum``    ``// of the given series``    ``static` `double` `sum(``int` `x, ``int` `n)``    ``{``        ``double` `i, total = ``1.0``, multi = x;` `        ``// First Term``        ``System.out.print(``"1 "``);` `        ``// Loop to print the N terms``        ``// of the series and compute``        ``// their sum``        ``for` `(i = ``1``; i < n; i++) {``            ``total = total + multi;``            ``System.out.print(multi);``            ``System.out.print(``" "``);``            ``multi = multi * x;``        ``}` `        ``System.out.println();``        ``return` `total;``    ``}` `    ``// Driver Code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``int` `x = ``2``;``        ``int` `n = ``5``;``        ``System.out.printf(``            ``"%.2f"``, sum(x, n));``    ``}``}`

## Python3

 `# Python3 program to find sum of``# series of 1 + x^2 + x^3 + ....+ x^n` `# Function to find the sum of``# the series and print N terms``# of the given series``def` `sum``(x, n):``    ` `    ``total ``=` `1.0``    ``multi ``=` `x` `    ``# First Term``    ``print``(``1``, end ``=` `" "``)` `    ``# Loop to print the N terms``    ``# of the series and find their sum``    ``for` `i ``in` `range``(``1``, n):``        ` `        ``total ``=` `total ``+` `multi``        ``print``(``'%.1f'` `%` `multi, end ``=` `" "``)``        ``multi ``=` `multi ``*` `x``        ` `    ``print``(``'\n'``)``    ``return` `total;` `# Driver code``x ``=` `2``n ``=` `5``print``(``'%.2f'` `%` `sum``(x, n))` `# This code is contributed by Pratik Basu`

## C#

 `// C# implementation to find``// the sum of series``// 1 + x^2 + x^3 + ....+ x^n``using` `System;``class` `GFG{` `// C# code to print the sum``// of the given series``static` `double` `sum(``int` `x, ``int` `n)``{``    ``double` `i, total = 1.0, multi = x;` `    ``// First Term``    ``Console.Write(``"1 "``);` `    ``// Loop to print the N terms``    ``// of the series and compute``    ``// their sum``    ``for` `(i = 1; i < n; i++)``    ``{``        ``total = total + multi;``        ``Console.Write(multi);``        ``Console.Write(``" "``);``        ``multi = multi * x;``    ``}``    ``Console.WriteLine();``    ``return` `total;``}` `// Driver Code``public` `static` `void` `Main(String[] args)``{``    ``int` `x = 2;``    ``int` `n = 5;``    ``Console.Write(``"{0:F2}"``, sum(x, n));``}``}` `// This code is contributed by Rajput-Ji`

## Javascript

 ``
Output:
```1 2.0 4.0 8.0 16.0
31.00```

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