JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 24 February 2021, Shift 2, Maths Q69

Question 69 of 90 in this shift, Maths question 9 of 30, Section A.

Let

f

be a twice differentiable function defined on R such that

f(0)=1

f'(0)=2

and

f'(x)\neq0

for all

x\in

R. If

\begin{vmatrix}f(x)&f'(x)\\f'(x)&f''(x)\end{vmatrix}=0

, for all

x\in

R, then the value of

f(1)

lies in the interval :

(1) $(0, 3)$
(2) $(3, 6)$
(3) $(6, 9)$ Official answer
(4) $(9, 12)$

Official answer

Option 3

NTA final key.

Chapter: Determinants
Topic: Variable Separable Form
Idea tested: Determinant Form Differential Equations

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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.