For the function, f(x)=tan−1x+sin−1x+cos−1x
Domain is
Range is
f(x)=tan−1x+sin−1x+cos−1x
common domain is x∈[−1,1]
∴f(x)=tan−1x+π2
f(−1)=−π4+π2=π4
f(1)=π4+π2=3π4