Question

sum of the first n terms of an A.P. is 4n2+2n .find the nth term of the AP

Answer 1

i hope this will usful to u

Answer 2

Answer:

The nth term of the AP is 2 (4n -1)

Step-by-step explanation:

Step 1:

$\begin{array}{l}{S n=4 n^{2}+2 n} \\ {S_{1}=a_{1}=4+2}\end{array}$

= 6

Step 2:

$\mathrm{S}_{2}=4 \times 2^{2}+2 \mathrm{x} 2$

= 16 + 4

= 20

Step 3:

$\begin{array}{l}{\mathrm{a}_{2}=\mathrm{S}_{2}-\mathrm{a}_{1}} \\ {\mathrm{a}_{2}=20-6}\end{array}$

= 14

Step 4:

$\mathrm{d}=\mathrm{a}_{2}-\mathrm{a}_{1}$

= 14 - 6

= 8

Step 5:

$\mathbf{a}_{\mathbf{n}}=\mathbf{a}_{\mathbf{1}}+(\mathbf{n}-\mathbf{1}) \mathbf{d}$

= 6 + (n-1) 8

= 6 + 8n - 8

= 8n - 2

= 2 (4n -1)