Question

The sum of first $$n$$ terms of an A.P. is $$\left(4n^{2} + 2n\right)$$. The $$n$$th term of the A.P. is ______.

विकल्प

• $$(6n - 2)$$

• $$(8n - 2)$$

• $$(6n + 2)$$

• $$(8n - 2)$$

Answer 1

The sum of first $$n$$ terms of an A.P. is $$\left(4n^{2} + 2n\right)$$. The $$n$$th term of the A.P. is (8n – 2).

Explanation:

$$\mathrm{T}_{n} = \mathrm{S}_{n} - \mathrm{S}_{n - 1}$$

$$= (4n^{2} + 2n) - [4(n - 1)^{2} + 2(n - 1)]$$

$$= 8n - 2$$