Question

If the sum of n terms of an A.P is given by $S_n=n^2+n$, then the common difference of the A.P is

• A. 4
• B. 1
• C. 2
• D. 6

Answer 1

Answer: (C)

$S_n=n^2+n$
$S_1=1+1=2=T_1$
$S_2=2^2+2=6=T_1+T_2$
$\therefore T_2=S_2-S_1=4$
Common difference, $d=T_2-T_1$
$=4-2$
$=2$