Given two integers and . The task is to find the sum of the series **1/a + 2/a ^{2} + 3/a^{3} + … + n/a^{n}**.

**Examples:**

Input:a = 3, n = 3Output:0.6666667

The series is 1/3 + 1/9 + 1/27 which is

equal to 0.6666667Input:a = 5, n = 4Output:0.31039998

**Approach:** Run a loop from **1 to n** and get the term of the series by calculating **term = (i / a ^{i})**. Sum all the generated terms which is the final answer.

Below is the implementation of the above approach:

## C++

`// C++ program to find the sum of` `// the given series` `#include <stdio.h>` `#include <math.h>` `#include <iostream>` `using` `namespace` `std;` `// Function to return the` `// sum of the series` `float` `getSum(` `int` `a, ` `int` `n)` `{` ` ` `// variable to store the answer` ` ` `float` `sum = 0;` ` ` `for` `(` `int` `i = 1; i <= n; ++i)` ` ` `{` ` ` `// Math.pow(x, y) returns x^y` ` ` `sum += (i / ` `pow` `(a, i));` ` ` `}` ` ` `return` `sum;` `}` `// Driver code` `int` `main()` `{` ` ` `int` `a = 3, n = 3;` ` ` ` ` `// Print the sum of the series` ` ` `cout << (getSum(a, n));` ` ` `return` `0;` `}` `// This code is contributed` `// by Sach_Code` |

## Java

`// Java program to find the sum of the given series` `import` `java.util.Scanner;` `public` `class` `HelloWorld {` ` ` `// Function to return the sum of the series` ` ` `public` `static` `float` `getSum(` `int` `a, ` `int` `n)` ` ` `{` ` ` `// variable to store the answer` ` ` `float` `sum = ` `0` `;` ` ` `for` `(` `int` `i = ` `1` `; i <= n; ++i) {` ` ` `// Math.pow(x, y) returns x^y` ` ` `sum += (i / Math.pow(a, i));` ` ` `}` ` ` `return` `sum;` ` ` `}` ` ` `// Driver code` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `a = ` `3` `, n = ` `3` `;` ` ` `// Print the sum of the series` ` ` `System.out.println(getSum(a, n));` ` ` `}` `}` |

## Python 3

`# Python 3 program to find the sum of` `# the given series` `import` `math` `# Function to return the` `# sum of the series` `def` `getSum(a, n):` ` ` `# variable to store the answer` ` ` `sum` `=` `0` `;` ` ` `for` `i ` `in` `range` `(` `1` `, n ` `+` `1` `):` ` ` ` ` `# Math.pow(x, y) returns x^y` ` ` `sum` `+` `=` `(i ` `/` `math.` `pow` `(a, i));` ` ` ` ` `return` `sum` `;` `# Driver code` `a ` `=` `3` `; n ` `=` `3` `;` ` ` `# Print the sum of the series` `print` `(getSum(a, n));` `# This code is contributed` `# by Akanksha Rai` |

## C#

`// C# program to find the sum` `// of the given series` `using` `System;` `class` `GFG` `{` ` ` `// Function to return the sum` `// of the series` `public` `static` `double` `getSum(` `int` `a, ` `int` `n)` `{` ` ` `// variable to store the answer` ` ` `double` `sum = 0;` ` ` `for` `(` `int` `i = 1; i <= n; ++i)` ` ` `{` ` ` `// Math.pow(x, y) returns x^y` ` ` `sum += (i / Math.Pow(a, i));` ` ` `}` ` ` `return` `sum;` `}` `// Driver code` `static` `public` `void` `Main ()` `{` ` ` `int` `a = 3, n = 3;` ` ` `// Print the sum of the series` ` ` `Console.WriteLine(getSum(a, n));` `}` `}` `// This code is contributed by jit_t` |

## PHP

`<?php` `// PHP program to find the` `// sum of the given series` `// Function to return the` `// sum of the series` `function` `getSum(` `$a` `, ` `$n` `)` `{` ` ` `// variable to store the answer` ` ` `$sum` `= 0;` ` ` `for` `(` `$i` `= 1; ` `$i` `<= ` `$n` `; ++` `$i` `)` ` ` `{` ` ` `// Math.pow(x, y) returns x^y` ` ` `$sum` `+= (` `$i` `/ pow(` `$a` `, ` `$i` `));` ` ` `}` ` ` `return` `$sum` `;` `}` `// Driver code` `$a` `= 3;` `$n` `= 3;` `// Print the sum of the series` `echo` `(getSum(` `$a` `, ` `$n` `));` `// This code is contributed by akt_mit` `?>` |

## Javascript

`<script>` `// Javascript program to find the sum of the given series` ` ` `// Function to return the sum of the series` ` ` `function` `getSum( a, n) {` ` ` `// variable to store the answer` ` ` `let sum = 0;` ` ` `for` `(let i = 1; i <= n; ++i) {` ` ` `// Math.pow(x, y) returns x^y` ` ` `sum += (i / Math.pow(a, i));` ` ` `}` ` ` `return` `sum;` ` ` `}` ` ` `// Driver code` ` ` ` ` `let a = 3, n = 3;` ` ` `// Prlet the sum of the series` ` ` `document.write(getSum(a, n).toFixed(7));` `// This code contributed by Princi Singh` `</script>` |

**Output:**

0.6666667

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