JEE Main 2022 · MathsMultiple choiceSingle correctMediumApplication

JEE Main 29 July 2022, Shift 2, Maths Q12

Question 12 of 90 in this shift, Maths question 12 of 30, Section A.

The number of elements in the set

S=\left\{x\in\mathbb{R}:2\cos\left(\frac{x^2+x}{6}\right)=4^x+4^{-x}\right\}

is :

(1) $1$ Official answer
(2) $3$
(3) $0$
(4)infinite

Official answer

Option 1

NTA final key.

Chapter: Trigonometric Functions
Topic: General Solutions
Idea tested: AM-GM Inequality Bounds in Trig Equations

Same topic in other shifts

All General Solutions questions

2 Apr 2026, Shift 1 · Q12Let $S=\{x \in [-\pi, \pi] : \sin x(\sin x+\cos x)=a, a \in \mathbb{Z}\}$ . Then $n(S)$ is equal to :HardSingle correct
5 Apr 2026, Shift 2 · Q23If $S=\left\{\theta \in [-\pi, \pi] : \cos\theta\cos\frac{5\theta}{2}=\cos 7\theta\cos\frac{7\theta}{2}\right\}$ , then n(S) is equal to…HardNumerical value
6 Apr 2026, Shift 1 · Q14Let $\mathrm{S}=\left\{\theta\in(-2\pi,2\pi):\cos\theta+1=\sqrt{3}\sin\theta\right\}$ . Then $\sum_{\theta\in \mathrm{S}}\theta$ is equal to:MediumSingle correct
2 Apr 2025, Shift 1 · Q3If $\theta\in[-2\pi, 2\pi]$ , then the number of solutions of $2\sqrt{2}\cos^2\theta+(2-\sqrt{6})\cos\theta-\sqrt{3}=0$ , is equal to :MediumSingle correct
2 Apr 2025, Shift 2 · Q13If $\theta \in \left[-\frac{7\pi}{6}, \frac{4\pi}{3}\right]$ , then the number of solutions of…MediumSingle correct
3 Apr 2025, Shift 1 · Q10The number of solutions of the equation $2x + 3\tan x = \pi$ , $x \in [-2\pi, 2\pi] - \left\{\pm\frac{\pi}{2}, \pm\frac{3\pi}{2}\right\}$ is: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.