JEE Main 2019MathematicsDifferentiationEasyMCQ

JEE Main 2019 — Differentiation Question with Solution

JEE Main 2019 (08 Apr Shift 2)

Question

If f1=1,f'1=3, then the derivative of fffx+fx2 at x=1 is:

Choose an option

Show full solutionCorrect option: D
Correct answer
D33

Step-by-step explanation

y=fffx+fx2

⇒dydx=f'ffx×f'fx×f'x+2fx×f'x

⇒dydxx=1=f'ff1×f'f1×f'1+2f1×f'1

=f'f1×f'1×3+2×1×3

=f'1×3×3+6

=3×3×3+6

=27+6

=33

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About this question

This is a previous-year question from JEE Main 2019, covering the Differentiation 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.