JEE Main 2020 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 3 September 2020, Shift 1, Maths Q51

Question 51 of 75 in this shift, Maths question 1 of 25.

Consider the two sets :

A=\{m\in\mathbf{R}

: both the roots of

x^2-(m+1)x+m+4=0

are real

\}

and

B=[-3,5)

. Which of the following is not true ?

(1) $A\cup B=\mathbf{R}$
(2) $A\cap B=\{-3\}$
(3) $A-B=(-\infty,-3)\cup(5,\infty)$ Official answer
(4) $B-A=(-3,5)$

Official answer

Option 3

NTA final key (Sep 2020).

Chapter: Complex Numbers and Quadratic Equations
Topic: Quadratic Roots
Idea tested: Nature of Roots

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Asked 9× in all

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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.