JEE Main 2019 — Functions Question with Solution
From: JEE Main 2019 (Online) 9th January Morning Slot
Question
For , Let f1(x) = , f2 (x) = 1 – x
and f3 (x) = be three given
functions. If a function, J(x) satisfies
(f2 o J o f1) (x) = f3 (x) then J(x) is equal to :
and f3 (x) = be three given
functions. If a function, J(x) satisfies
(f2 o J o f1) (x) = f3 (x) then J(x) is equal to :
Choose an option
Show full solutionCorrect option: D
Correct answer
Df3 (x)
Step-by-step explanation
Given,
f1(x) =
f2(x) = 1 x
f3(x) =
(f2 J f1) (x) = f3(x)
f2 {J(f1(x))} = f3(x)
f2{J ()} =
1 J() =
J() = 1
J () = =
Put x inplace of
J(x) =
=
f1(x) =
f2(x) = 1 x
f3(x) =
(f2 J f1) (x) = f3(x)
f2 {J(f1(x))} = f3(x)
f2{J ()} =
1 J() =
J() = 1
J () = =
Put x inplace of
J(x) =
=
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This is a previous-year question from JEE Main 2019, covering the Functions 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.