The sum of the first terms of a sequence is given by .

MATHEMATICS · Multi-part · CBSE · Mathematics · Arithmetic Progressions · Arithmetic Progressions

Problem

The sum of the first

n

terms of a sequence is given by

S_n = 4n^2 + 3n

. (a) Obtain an expression for the

n

th term

a_n

of the sequence. (b) Show that the sequence whose terms are

a_1, a_2, a_3, \ldots

forms an arithmetic progression. (c) Find the first term and the common difference of this progression. (d) Calculate the 20th term.