Choose the correct answer from the given four options:
If the first term of an $ \mathrm{AP} $ is $ -5 $ and the common difference is 2 , then the sum of the first 6 terms is
(A) 0
(B) 5
(C) 6
(D) 15
Given:
The first term of an \( \mathrm{AP} \) is \( -5 \) and the common difference is 2.
To do:
We have to find the sum of the first 6 terms.
Solution:
First term $a_1 = a= -5$
Common difference $d =2$
We know that,
Sum of the $n$ terms of an AP is $S_n=\frac{n}{2}[2a+(n-1)d]$
Therefore,
$S_6= \frac{6}{2}[2(-5)+(6-1)2]$
$= 3(-10+10)$
$= 0$
The sum of the first 6 terms of the AP is $0$.
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