Question

Find the sum of the series whose nth term is given by:

(3n² + 2n)

Answer 1

It is given in the question that the n^th term of the series,

a_n = 3n² + 2n

Now, we need to find the sum of this series, S_n.

Note:

I. Sum of first n natural numbers, 1 + 2 + 3 +…n,

II. Sum of squares of first n natural numbers, 1² + 2² + 3² +….n²,

III. Sum of cubes of first n natural numbers, 1³ + 2³ + 3³ +…..n³,

IV. Sum of a constant k, N times,