Iterative Constructs in Java

Chapter 9

Iterative Constructs in Java

Class 10 - Logix Kips ICSE Computer Applications with BlueJ

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Java Program: Sum of n/xⁿ Series

30(iii). Write a program in Java to find the sum of the given series:

\[ \frac{1}{x^{1}} + \frac{2}{x^{2}} + \frac{3}{x^{3}} + \cdots + \frac{n}{x^{n}} \]

Program Title: Sum of n/xⁿ Series

import java.util.Scanner;
 
public class SumSeries {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 
        System.out.print("Enter the value of x: ");
        double x = sc.nextDouble();
 
        System.out.print("Enter the number of terms n: ");
        int n = sc.nextInt();
 
        double sum = 0.0;
 
        for (int i = 1; i <= n; i++) {
            sum += i / Math.pow(x, i);
        }
 
        System.out.println("Sum of the series is: " + sum);
 
        sc.close();
    }
}
 

Sample Input / Output
Enter the value of x: 2
Enter the number of terms n: 5
Sum of the series is: 1.59375

📝 Explanation

\[ \frac{1}{2^{1}} + \frac{2}{2^{2}} + \frac{3}{2^{3}} + \frac{4}{2^{4}} + \frac{5}{2^{5}} = 0.5+0.5+0.375+0.25+0.15625=1.59375 \]

How it works

1. Loop from i = 1 to n
2. For each term, calculate i / x^i using Math.pow(x, i)
3. Add to sum
4. Print the final sum