JEE Main 2019MathematicsApplication Of DerivativesMaxima And MinimamediumMCQ

JEE Main 2019 — Application Of Derivatives Question with Solution

From: JEE Main 2019 (Online) 8th April Morning Slot

Question

If S1 and S2 are respectively the sets of local minimum and local maximum points of the function,

ƒ(x) = 9x4 + 12x3 – 36x2 + 25, x R, then :

Choose an option

Show full solutionCorrect option: D
Correct answer
DS1 = {–2, 1}; S2 = {0}

Step-by-step explanation

ƒ(x) = 9x4 + 12x3 – 36x2 + 25

ƒ'(x) = 36x3 + 36x2 – 72x

ƒ'(x) = 36x(x2 + x – 2)

ƒ'(x) = 36x(x + 2)(x - 1) JEE Main 2019 (Online) 8th April Morning Slot Mathematics - Application of Derivatives Question 162 English Explanation

While moving left to right on x-axis whenever derivative changes sign from negative to positive, we get local minima, and whenever derivative changes sign from positive to negative, we get local maxima.

S1 = {–2, 1}

S2 = {0}

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About this question

This is a previous-year question from JEE Main 2019, covering the Application Of Derivatives chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.