JEE Main 2021MathematicsInverse Trigonometric FunctionsMediumMCQ

JEE Main 2021 — Inverse Trigonometric Functions Question with Solution

JEE Main 2021 (26 Feb Shift 1)

Question

If sin-1xa=cos-1xb=tan-1yc;0<x<1, then the value of cosπca+b is:

Choose an option

Show full solutionCorrect option: A
Correct answer
A1-y21+y2

Step-by-step explanation

sin-1xr=a,cos-1xr=b,tan-1yr=c

So, a+b=π2r

cosπca+b=cosπtan-1yπ2rr

=cos2tan-1y, let tan-1y=θ

=cos2θ

=1-tan2θ1+tan2θ=1-y21+y2

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About this question

This is a previous-year question from JEE Main 2021, covering the Inverse Trigonometric Functions chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.