# How to sum a series with the last term being the denominator of user input in Java [closed]

In the series: 1/3 + 3/5 + 5/7 + 7/9 + 9/11 +.........#/nth, I am trying to make the nth the denominator of a series such as if the user inputted 5 it would compute 1/3 + 3/5, 5 being the last term which the user inputted. I was able to make the code compute the number of terms such as 5 would compute 5 terms 1/3 + 3/5 + 5/7+ 7/9 + 9/11 . here is my code:

``````import java.util.Scanner;
public class n01092281
{
//for loop that computes a sum of the series
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Enter your nth term for the series.");
double userInput = input.nextInt();
double sum = 0.0;
for(int i = 2; i <= userInput*2; i+=2) {
sum += ((double)(i-1)/(i+1));
}
}
}
``````

The problem is with your for loop conditions. You are looping it for `userInput*2` times. Subtract it by `2` and initialize `i` to `1` since your series starts with 1 as numerator.

``````import java.util.Scanner;

public class n01092281 {
//for loop that computes a sum of the series
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Enter your nth term for the series.");
double userInput = input.nextInt();
double sum = 0.0;
for (double i = 1; i <= userInput - 2; i += 2) {
sum += (i / (i + 2));
}
System.out.println(sum);
}
}
``````