Consider an arithmetic progression whose first term is 7 and common difference is 3

MATHEMATICS · Multi-part · A Level · Mathematics · Sequences and series · Sequences and series

Problem

Consider an arithmetic progression whose first term is 7 and common difference is 3. The progression contains

(2n+1)

terms. (i) Write the last term of the progression in terms of

n

. (ii) Derive an expression for the sum

S

of all

(2n+1)

terms in terms of

n

. (iii) Simplify your expression for

S

. (iv) Using your result, find the value of

S

when

n = 12