tanπ4+12cos−1x+tanπ4−12cos−1x,x≠0 is equal to
x
2x
2/x
none of these
Let cos–1x = θ, then the given expression=1+tanθ21−tanπ2+1+tanθ21+tanθ2=21+tan2θ21−tan2θ2=2cosθ=2x