Range of f(x)=sin−1x+tan−1x+sec−1x is
π4,3π4
None of these
We have, f(x)=sin−1x+tan−1x+sec−1x Domain of sin−1x is -1, 1 Domain of tan−1x is (−∞,∞) Domain of sec−1x is (−∞,−1]∪[1,∞) ∴ Domain of f(x)={−1,1} Thus, range of f(x)={f(1),f(−1)} i.e. sin−11+tan−11+sec−11=π2+π4+0=3π4 and sin−1(−1)+tan−1(−1)+sec−1(−1)=−π2−π4+π=π4 ∴ Range is π4,3π4.