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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 16 March 2021, Shift 2, Maths Q78

Question 78 of 90 in this shift, Maths question 18 of 30, Section A.

Given that the inverse trigonometric functions take principal values only. Then, the number of real values of xx which satisfy sin⁡−1(3x5)+sin⁡−1(4x5)=sin⁡−1x\sin^{-1}\left(\frac{3x}{5}\right)+\sin^{-1}\left(\frac{4x}{5}\right)=\sin^{-1}x is equal to :
  1. (1)0
  2. (2)1
  3. (3)2
  4. (4)3Official answer

Official answer

Option 4

NTA final key.

Chapter
Inverse Trigonometric Functions
Topic
Inverse Trig Identities
Idea tested
Sine Inverse Sum and Difference

Same idea in other shifts

Asked 3× in all
  1. 13 Apr 2023, Shift 1 · Q30If…HardNumerical value
  2. 3 Sep 2020, Shift 1 · Q692π−(sin⁡−145+sin⁡−1513+sin⁡−11665)2\pi-\left(\sin^{-1}\frac{4}{5}+\sin^{-1}\frac{5}{13}+\sin^{-1}\frac{16}{65}\right) is equal to :MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.