Choose the correct answer.
∫1x2+2x+2dx equals
(a)xtan−1(x+1)+C(b)tan−1(x+1)+C(c)(x+1)tan−1x+C(d)tan−1x+C
Let I=∫1x2+2x+2dx=∫1(x+1)2+12dxLet x+1=t⇒dx=dt
∴I=∫1t2+12dx=11tan−1(t1)+C[∵∫dxa2+x2=1atan−1(xa)]=tan−1(x+11)+C=tan−1(x+1)+C
Hence, the option (b)is correct.