Consider an arithmetic progression in which the third term is and the fifteenth term is .

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

Problem

Consider an arithmetic progression in which the third term is

12

and the fifteenth term is

48

. (i) Find the general term

a_n

of the progression. (ii) Obtain an expression for the sum

S_n

of the first

n

terms in terms of

n

only.