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Saturday, 31 October

JEE Main 2022 · MathsMultiple choiceSingle correctEasyApplication

JEE Main 30 June 2022, Shift 1, Maths Q9

Question 9 of 90 in this shift, Maths question 9 of 30, Section A.

Let f(x)=4x3−11x2+8x−5f(x) = 4x^3 - 11x^2 + 8x - 5, x∈Rx \in \mathbf{R}. Then ff :
  1. (1)has a local minima at x=12x = \frac{1}{2}
  2. (2)has a local minima at x=34x = \frac{3}{4}
  3. (3)is increasing in (12,34)\left(\frac{1}{2}, \frac{3}{4}\right)
  4. (4)is decreasing in (12,43)\left(\frac{1}{2}, \frac{4}{3}\right)Official answer

Official answer

Option 4

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. 28 Jul 2022, Shift 2 · Q66The function f(x)=xex(1−x), x∈Rf(x)=xe^{x(1-x)},\ x\in\mathbb{R}, is :MediumSingle 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.