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Question: Answered & Verified by Expert
The value of tan-11+x2+ 1-x21+x2- 1-x2, x<12, x0, is equal to:
MathematicsInverse Trigonometric FunctionsJEE MainJEE Main 2017 (08 Apr Online)
Options:
  • A π4+12cos-1x2
  • B π4-cos-1x2
  • C π4-12cos-1x2
  • D π4+cos-1x2
Solution:
1919 Upvotes Verified Answer
The correct answer is: π4+12cos-1x2
Assume that ,
x2=cos2θ;θ=12cos-1x2

tan- 11+cos2θ+ 1-cos2θ1+cos2θ- 1-cos2θ=tan- 12cos2θ+ 2sin2θ2cos2θ- 2sin2θ=tan- 1cosθ+ sinθcosθ- sinθ
=tan-11+tanθ1-tanθ

=tan-1tanπ4+θ

=π4+12cos-1x2

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