JEE Main 2020MathematicsInverse Trigonometric FunctionsMediumNumerical

JEE Main 2020 — Inverse Trigonometric Functions Question with Solution

JEE Main 2020 (02 Sep Shift 2)

Question

 If y=∑k=16kcos-135coskx-45sinkx then dydx at x=0is
 

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Show full solutionCorrect answer: 91
Correct answer
91

Step-by-step explanation

For, small values near 0, i.e., x<<..1

y=∑k=16kcos-1coskx·cosα-sinkx·sinα

=∑k=16kcos-1coskx+α
=∑k=16kkx+α

=∑k=16k2x+kα

 dydx=∑k=16k2=67136=91 

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About this question

This is a previous-year question from JEE Main 2020, 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.