Question

find the sum of first n terms of a AP whose nth term is 3n+7​

Answer 1

Answer:

$\frac{n}{2} [ 3n+17 ]$

Step-by-step explanation:

Given ntn term is 3n+7.

i.e, $a_n$ = 3n+7

Then our first term is,

⇒ $a_1$ = 3(1)+7

        = 3+7

        = 10

Sum of first n terms in an AP is given by $S_n$ = $\frac{n}{2}$[$a_1 + a_n$]

⇒ $S_n = \frac{n}{2} [10 + 3n+7]$

         = $\frac{n}{2} [ 3n+17 ]$

Answer 2

Answer:

___________

$\huge{\underline{\mathtt{\red{❥A}\pink{N}\green{S}\blue{W}\purple{E}\orange{R}}}}$ hi my dear here is your answer