The correct option is B 12log(1+x22+x2+2x)+tan−1(x+1)+C
I=∫cot1(x2+x+1)dx=∫tan−1(1x2+x+1)dx=∫tan−1(11+x(1+x))dx=∫(tan−1(x+1)−tan−1(tan−1x))dx=∫tan−1(x+1)dx+∫tan−1(x)dxI1=∫tan−1(x+1)dx
Putx+1=tdx=dtI1=∫tan−1tdt=ttan−1t−∫t1+t2dt=ttan−1t−12log(1+t2)+C=(1+x)tan−1(x+1)−12log[1+(1+x2)]+C
I2=∫tan−1(x)dx=xtan−1x−12log(1+x2)+C