The sum of the first n terms of the A.P. -2, | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) The given $A.P.$ is $-2, 1, 4, 7, \ldots$Here,the first term $a = -2$.The common difference $d = 1 - (-2) = 1 + 2 = 3$.The sum of the first $n$ te

Vedclass · Accepted Answer

$\frac{n(3n-7)}{2}$

Vedclass · Answer

(C) The given $A.P.$ is $-2, 1, 4, 7, \ldots$Here,the first term $a = -2$.The common difference $d = 1 - (-2) = 1 + 2 = 3$.The sum of the first $n$ terms of an $A.P.$ is given by the formula $S_n = \frac{n}{2}[2a + (n-1)d]$.Substituting the values of $a$ and $d$ into the formula:$S_n = \frac{n}{2}[2(-2) + (n-1)3]$$S_n = \frac{n}{2}[-4 + 3n - 3]$$S_n = \frac{n(3n - 7)}{2}$.

The sum of the first $n$ terms of the $A.P.$ $-2, 1, 4, 7, \ldots$ is:

Similar Questions

For the $A.P.$ $3, 8, 13, 18, \ldots$,$T_{n} = \ldots$

If $S_{n}$ denotes the sum of the first $n$ terms of an $AP$,prove that $S_{12} = 3(S_{8} - S_{4})$.

The sum of three numbers in $A.P.$ is $12$ and the sum of their cubes is $288$. Find those numbers.

For the finite $A.P.$ $5, 9, 13, \ldots, 101$,find the $9^{th}$ term from the end.

For an $A.P.$,$T_{n} = \ldots \ldots \ldots \ldots (n > 1)$

Vedclass Test Series

Exam Paper Generator

Online Exam Module