JEE Main 2026 · MathsNumerical answerNumerical valueHardMulti-step

JEE Main 5 April 2026, Shift 2, Maths Q23

Question 23 of 75 in this shift, Maths question 23 of 25, Section B.

S=\left\{\theta \in [-\pi, \pi] : \cos\theta\cos\frac{5\theta}{2}=\cos 7\theta\cos\frac{7\theta}{2}\right\}

, then n(S) is equal to __________.

Official answer

NTA final key.

Chapter: Trigonometric Functions
Topic: General Solutions
Idea tested: Product-to-Sum Transformation

Same idea in other shifts

Asked 2× in all

24 Jun 2022, Shift 2 · Q13The number of solutions of the equation $\cos\left(x + \frac{\pi}{3}\right)\cos\left(\frac{\pi}{3} - x\right) = \frac{1}{4}\cos^2 2x$ ,…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.