程序来查找级数之和(1 / a + 2 / a ^ 2 + 3 / a ^ 3 +…+ n / a ^ n)

给定两个整数$a$和$n$ 。任务是找到1 / a + 2 / a ² + 3 / a ³ +…+ n / a ^n的和。
例子：

Input: a = 3, n = 3 
Output: 0.6666667 
The series is 1/3 + 1/9 + 1/27 which is 
equal to 0.6666667
Input: a = 5, n = 4 
Output: 0.31039998 
 

方法：运行从1到n的循环并获得$i-th$通过计算项=(i / a ⁱ )来级数的项。总结所有生成的术语，这是最终答案。
下面是上述方法的实现：

C++

// C++ program to find the sum of
// the given series
#include 
#include 
#include 
 
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

Javascript

 
// 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
 

输出：

0.6666667