Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N

Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N

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In the previous article we have discussed about Java Program to Find the Sum of Series 1 + (1/2) + (1/3) + … + N

In this article we are going to see how to print sum of the series 1 + (1/3) + (1/5) + … + N by using Java programming language.

Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N

On observing the pattern carefully, we can see each term is in a/b format.

Numerator = 1 (Fixed)

Denominator = Odd number starting from 1

Like

1st term=1/1

2nd term=1/2

3rd term=1/3 like this.

And the series= 1/1+1/2+1/3 like this.

And our task is to first form the series and then find the sum of the series.

Let’s see different ways to print sum of the series 1 + (1/3) + (1/5) + … + N.

Example:

Suppose value of n = 3

1 + (1/2) + (1/3) = 1 + 0.5 + 0.34 = 1.84

Method-1: Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N By Using For Loop

Approach:

  • Declare an integer variable say ‘n’ which holds the value of Nth term.
  • Create Scanner class object.
  • Prompt the user to enter a number as value of n.
  • Declare an long variable say ‘sum‘ and initialize it to 0.
  • Declare an integer variable ‘count‘ and initialize it to 1.
  • Then declare integer variable m=n*n;
  • Use a for loop from i=1 to i<=m (incremented by 2)
  • Inside the for loop, find each term and add it to sum. Also keep track on count variable if count==n then break the loop.
  • Print the result.

Program:

import java.util.*;
public class Main
{
  public static void main (String[]args)
  {
    //creating object of Scanner class 
    Scanner s = new Scanner (System.in);
    //Taking input of number of elements in the series
    System.out.println ("Enter the value of 'n' ");
    int n = s.nextInt ();
    double sum = 0;
    int count=1;
    int m = n * n;
    //for loop to print the series
    for (int i = 1; i <= m; i += 2)
      {
    	System.out.println (1.0 / i);
        sum += (1.0 / i);
        if(count == n)
            break;
        count++;
      }
    System.out.println ("Sum of the series is " + sum);
  }
}

Output:

Enter the value of 'n' 
3
1.0
0.3333333333333333
0.2
Sum of the series is 1.5333333333333332

Method-2: Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N By Using While Loop

Approach:

  • Declare an integer variable say ‘n’ which holds the value of Nth term.
  • Create Scanner class object.
  • Prompt the user to enter a number as value of n.
  • Declare an long variable say ‘sum‘ and initialize it to 0.
  • Declare an integer variable ‘count‘ and initialize it to 1.
  • Then declare integer variable m=n*n;
  • Declare an integer variable ‘i‘ and initialize it to 1.
  • Use a while loop till i<=m (incremented by 2)
  • Inside the while loop, find each term and add it to sum.  Also keep track on count variable if count==n then break the loop.
  • Print the result.

Program:

import java.util.*;
public class Main
{
  public static void main (String[]args)
  {
    //creating object of Scanner class 
    Scanner s = new Scanner (System.in);
    //Taking input of number of elements in the series
    System.out.println ("Enter the value of 'n' ");
    int n = s.nextInt ();
    double sum = 0;
    int count=1;
    int m = n * n;
    int i=1;
    //while loop to print the series
    while (i <= m)
      {
    	System.out.println (1.0 / i);
        sum += (1.0 / i);
        if(count == n)
            break;
        count++;
        i+=2;
      }
    System.out.println ("Sum of the series is " + sum);
  }
}

 

Output:

Enter the value of 'n' 
3
1.0
0.3333333333333333
0.2
Sum of the series is 1.5333333333333332

Method-3: Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N By Using While Loop

Approach:

  • Declare an integer variable say ‘n’ which holds the value of Nth term.
  • Create Scanner class object.
  • Prompt the user to enter a number as value of n.
  • Then call a user defined method say printSeries() by passing n as parameter.
  • Inside method declare an long variable say ‘sum‘ and initialize it to 0.
  • Declare an integer variable ‘count‘ and initialize it to 1.
  • Then declare integer variable m=n*n;
  • Use a for loop from i=1 to i<=m (incremented by 2)
  • Inside the for loop, find each term and add it to sum.  Also keep track on count variable if count==n then break the loop.
  • Print the result.

Program:

import java.util.*;
public class Main
{
  public static void main (String[]args)
  {
    //creating object of Scanner class 
    Scanner s = new Scanner (System.in);
    //Taking input of number of elements in the series
    System.out.println ("Enter the value of 'n' ");
    int n = s.nextInt ();
    //calling printSeries() method to print the series
    printSeries(n);
   }
    
   public static void printSeries(int n)
    {
    double sum = 0;
    int count=1;
    int m = n * n;
    int i=1;
    //for loop to print the series
    while (i <= m)
      {
    	System.out.println (1.0 / i);
        sum += (1.0 / i);
        if(count == n)
            break;
        count++;
        i+=2;
      }
    System.out.println ("Sum of the series is " + sum);
  }
}
Output: 

Enter the value of 'n' 
3
1.0
0.3333333333333333
0.2
Sum of the series is 1.5333333333333332

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