If S=(1+3)+(5+7+9+11)+(13+15+17+19+21+23)+...... upto n terms then find S

Hii

In complte sense it is nothing but the sum of odd natural numbers but the term number is a bit tricky .In nth term we will have 2n terms and 2n-2 in previous term.

So add numbers like this to get the total numbers of terms you will get the answer as sum of odd terms for n terms is N²