Which of the following is the correct expression for the th term of an arithmetic…

MATHEMATICS · Single correct · A Level · Mathematics · Sequences and series · Sequences and series

Problem

Which of the following is the correct expression for the

n

th term of an arithmetic progression whose first term is

a

and common difference is

d

? (a)

a_n = a + nd

(b)

a_n = \dfrac{n}{2}\bigl(2a + (n-1)d\bigr)

(c)

a_n = a + (n-1)d

(d)

a_n = a(1+d)^{\,n-1}