Question

The n^th term of the A.P. a, 3a, 5a, ... is ______.

Options

• na

• (2n – 1)a

• (2n + 1)a

• 2na

Answer 1

The n^th term of the A.P. a, 3a, 5a, ... is (2n – 1)a.

Explanation:

Given, A.P. = a, 3a, 5a, ...

Here first term, a = a and d = 3a – a = 2a

∴ n^th term = a + (n – 1)d

= a + (n – 1)2a

= a + 2na – 2a

= 2na – a

= (2n – 1)a