The correct option is C {π4,3π4}
Domain of sin−1x is (−1,1].
Domain of tan−1x is R.
Domain of sec−1x is
(−∞,−1] ∪[1,∞).
So, domain of
sin−1x+tan−1x+sec−1x is theintersection of all these three domainsi.e., (−1,1}.
For x = −1,sin−1x+tan−1x+sec−1x= sin−1(−1)+tan−1(−1)+sec−1(−1)= −π2 − π4 + π= π4.
Similarly, For x = 1,sin−1x+tan−1x+sec−1x= π2 +π4 + 0= 3π4.
Therefore, the range is
(π4, 3π4}.