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Question: Answered & Verified by Expert
If sin-1x+tan-1x=π/2, then 2x2+1=
MathematicsInverse Trigonometric FunctionsBITSATBITSAT 2019
Options:
  • A 5
  • B 5-12
  • C 2
  • D 5+12
Solution:
1090 Upvotes Verified Answer
The correct answer is: 5

We have,

sin-1x+tan-1x=π20<x<1

 tan-1x=π2-sin-1x=cos-1x

 tan-1x=tan-11-x2x

 x2=1-x2

 x4+x2-1=0x2=-1±52

as x2>0

 x2=5-12

2x2+1=5

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