Question

If nth term is n(n+3) then the sum of first n terms of the series is

Answer 1

Answer:

The sum of the nth term of n is n(n+1)/2

The sum of the nth term of n² = n(n+1)(2n+1)/6

Then let £ = Sigma Notation

£ n(n+3) = £ n²+3n

£ n² + £ 3n = £ n² + 3£n

£ n² + 3£n = (n(n+1)(2n+1)/6)) + (3n(n+1)/2)