If f(x)=x,g(x)=ex−1 and h(x)=tan−1⁡x then the anti derivative of (f o g) (x) is

I=∫ex−1dxPut ex−1=t2, so that  exdx=2tdt∴I=∫t2tt2+1dt=2∫t2+1−1t2+1dt=2t−tan−1⁡t+C=2ex−1−tan−1⁡ex−1+C=2[( fog )(x)−( hofog )(x)]+C.