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JEE Main 2020 · MathsMultiple choiceSingle correctEasyApplication

JEE Main 6 September 2020, Shift 2, Maths Q58

Question 58 of 75 in this shift, Maths question 8 of 25.

Let

f:\mathbf{R}\to\mathbf{R}

be a function defined by

f(x)=\max\{x,x^2\}

. Let S denote the set of all points in

\mathbf{R}

, where

f

is not differentiable. Then :

(1) $\phi$ (an empty set)
(2) $\{0,1\}$ Official answer
(3) $\{0\}$
(4) $\{1\}$

Official answer

Option 2

NTA final key (Sep 2020).

Chapter: Continuity and Differentiability
Topic: Continuity and Differentiability
Idea tested: Differentiability of Max/Min Functions

Same idea in other shifts

Asked 2× in all

4 Apr 2026, Shift 1 · Q25The number of points, at which the function $f(x)=\max\{6x,\ 2+3x^2\}+|x-1|\cos\left|x^2-\frac14\right|$ , $x\in(-\pi,\pi)$ , is not…HardNumerical value

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.