AP EAMCET202120 Aug 2021Morning ShiftMathematicsInverse Trigonometric FunctionsActual
If x = sin 2 tan - 1 2 , y = cos 2 tan - 1 3 , z = sec 3 tan - 1 4 then
Options
- Ax < y < z
- By < z < x
- Cz < x < y
- Dz < y < x
Correct answer
D. z < y < x
Step-by-step solution
We know, 2 tan - 1 x = sin - 1 ( 2 x 1 + x 2 )   = cos - 1 ( 1 - x 2 1 + x 2 ) = sec - 1 ( 1 + x 2 1 - x 2 ) ∴ x = sin 2 tan - 1 2     =   sin sin - 1 2 2 1 + 2 2   =   4 5 y = cos 2 tan - 1 3   =   cos cos - 1 ( 1 - 3 2 1 + 3 2 )   =   - 4 5 z = sec 2 tan - 1 4   sec sec - 1 ( 1 + 4 2 1 - 4 2 )   =   - 5 4 ∴ z < y < x