The correct option is C π2
∫π0tan xsec x+cos xdx=∫π0sin xcos x1cos x+cos xdx=∫π0sin x1+cos2xdx
Put cos x = t
Then - sin x dx = dt
x = 0 ⇒ t = cos 0 = 1
∫π0sin x1+cos2xdx=∫−11 11+t2(−dt)=[tan−1(t)]1−1=tan−1(1)−tan−1(−1)
=tan−11+tan−11=2 tan−1(1)=2.π4=π2