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Saturday, 31 October

JEE Main 2022 · MathsMultiple choiceSingle correctMediumApplication

JEE Main 28 July 2022, Shift 2, Maths Q66

Question 66 of 90 in this shift, Maths question 6 of 30, Section A.

The function f(x)=xex(1−x), x∈Rf(x)=xe^{x(1-x)},\ x\in\mathbb{R}, is :
  1. (1)increasing in (−12,1)\left(-\frac{1}{2},1\right)Official answer
  2. (2)decreasing in (12,2)\left(\frac{1}{2},2\right)
  3. (3)increasing in (−1,−12)\left(-1,-\frac{1}{2}\right)
  4. (4)decreasing in (−12,12)\left(-\frac{1}{2},\frac{1}{2}\right)

Official answer

Option 1

NTA final key.

Same idea in other shifts

Asked 7× in all
  1. 8 Apr 2025, Shift 2 · Q17Let the function f(x)=x3+3x+3f(x) = \frac{x}{3} + \frac{3}{x} + 3, x≠0x \neq 0 be strictly increasing in…EasySingle correct
  2. 1 Feb 2024, Shift 1 · Q7If 5f(x)+4f(1x)=x2−2, ∀ x≠05f(x)+4f\left(\frac{1}{x}\right)=x^2-2,\ \forall\ x\neq0 and y=9x2f(x)y=9x^2f(x), then yy is strictly increasing in :HardSingle correct
  3. 30 Jun 2022, Shift 1 · Q9Let f(x)=4x3−11x2+8x−5f(x) = 4x^3 - 11x^2 + 8x - 5, x∈Rx \in \mathbf{R}. Then ff :EasySingle correct
  4. 25 Jul 2021, Shift 1 · Q67Let f(x)=3sin⁡4x+10sin⁡3x+6sin⁡2x−3f(x)=3\sin^4x+10\sin^3x+6\sin^2x-3, x∈[−π6,π2]x\in\left[-\frac{\pi}{6},\frac{\pi}{2}\right]. Then, ff is :MediumSingle correct
  5. 16 Mar 2021, Shift 2 · Q64Let ff be a real valued function, defined on R−{−1,1}\mathbf R-\{-1,1\} and given by f(x)=3log⁡e∣x−1x+1∣−2x−1f(x)=3\log_e\left|\frac{x-1}{x+1}\right|-\frac{2}{x-1}.…MediumSingle correct
  6. 3 Sep 2020, Shift 1 · Q59The function, f(x)=(3x−7)x2/3f(x)=(3x-7)x^{2/3}, x∈Rx\in\mathbf{R}, is increasing for all xx lying in :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.