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JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 16 March 2021, Shift 2, Maths Q77

Question 77 of 90 in this shift, Maths question 17 of 30, Section A.

The maximum value of

f(x)=\begin{vmatrix}\sin^2x & 1+\cos^2x & \cos2x\\ 1+\sin^2x & \cos^2x & \cos2x\\ \sin^2x & \cos^2x & \sin2x\end{vmatrix}

,

x\in\mathbf R

is :

(1) $\sqrt5$ Official answer
(2)5
(3) $\sqrt7$
(4) $\frac34$

Official answer

Option 1

NTA final key.

Chapter: Determinants
Topic: Trigonometric Identities
Idea tested: Extrema of Linear Trigonometric Forms

Same idea in other shifts

Asked 2× in all

9 Apr 2024, Shift 2 · Q1Let the range of the function $f(x)=\frac{1}{2+\sin 3x+\cos 3x},\ x\in\mathbb{R}$ be $[a, b]$ . If $\alpha$ and $\beta$ are respectively…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 42 of the 174 JEE Main shifts held from 2017 to 2026.