Q104 / 180 · KCET 2020 · Mathematics
If the sum of $n$ terms of an AP is given by $S_{n}=n^{2}+n$, then the common difference of the AP is
- A4
- B1
- Correct answerC2
- D6
Solution
Given sum of $n$ terms of an AP.
$\begin{aligned}
S_{n} &=n^{2}+n \\
a_{1} &=S_{1}=1+1=2 \\
a_{1}+a_{2} &=S_{2}=2^{2}+2=6 \\
a_{2} &=S_{2}-S_{1}=6-2=4 \\
d &=a_{2}-a_{1}=4-2=2
\end{aligned}$
Hence, the correct answer is option: 'C'.