Question

write a program in Java to find the sum of series of s= 2-4+6-8....to n terms ​

Answer 1

Explanation:

We loop all even number upto n, and then subtract multiples of 4 and add the rest.

public class SumOfSeries{

public static void main(String args[]){

int n = 20;int sum =0;

for(int i=2;i<=n;i=i+2){

if(i%4==0){ sum=sum-i;}

else{ sum=sum+i;}

}

System. out. println("Sum of series upto " + n + " terms is : " + sum);