Question

Print the series : S= a- a^3+ a^5 - a^7......... In java

Answer 1

Series Sum - Java

We can calculate the Sum of series till n terms. We need to take user input for two values:

• Value of a
• Number of terms n

Using these two values we can calculate the Series Sum. We would initialize a Sum variable to 0 and then run a loop from n times to get the Sum of n terms.

We need to first generalize the Sum in a Mathematical Form to be able to put it in the program.

Here's how we do it:

$S = a-a^3+a^5-a^7+\dots\\\\\\ \implies \Large\boxed{S = \sum\limits_{i=0}^{n-1} (-1)^i a^{2i+1}}$

We can easily put this in a loop to get the required Sum. For powers, we use the Math.pow() function.

$\rule{300}{1}$

import java.util.Scanner;   //Importing Scanner

public class SeriesSum      //Creating Class

{

   public static void main(String[] args)  //The main function

   {

       Scanner sc = new Scanner(System.in); //Creating Scanner Object

       //Take User Input for 'a'

       System.out.print("Enter the value of 'a': ");

       double a = sc.nextDouble();

       //Take User Input for number of terms (n)

       System.out.print("Enter the number of terms: ");

       int n = sc.nextInt();

       double Sum = 0; //Initialise Sum to 0

       for(int i=0;i<n;i++)    //Run a loop n times

       {

           //Add Terms to Sum

           Sum += Math.pow(-1,i) * Math.pow(a,(2*i+1));

       }

       //Print Final Series Sum

       System.out.println("The Series Sum is: "+Sum);

   }

}

Answer 2

Answer:

Explanation:

import java.util.Scanner; //Importing Scanner

public class SeriesSum //Creating Class

{

public static void main(String[] args) //The main function

{

Scanner sc = new Scanner(System.in); //Creating Scanner Object

//Take User Input for 'a'

System.out.print("Enter the value of 'a': ");

double a = sc.nextDouble();

//Take User Input for number of terms (n)

System.out.print("Enter the number of terms: ");

int n = sc.nextInt();

double Sum = 0; //Initialise Sum to 0

for(int i=0;i<n;i++) //Run a loop n times

{

//Add Terms to Sum

Sum += Math.pow(-1,i) * Math.pow(a,(2*i+1));

}

//Print Final Series Sum

System.out.println("The Series Sum is: "+Sum);

}

}