JEE Main 2021MathematicsFunctionsEasyMCQ

JEE Main 2021 — Functions Question with Solution

JEE Main 2021 (25 Feb Shift 2)

Question

A function f(x) is given by fx=5x5x+5, then the sum of the series

f120+f220+f320+…+f3920

is equal to:

Choose an option

Show full solutionCorrect option: C
Correct answer
C392

Step-by-step explanation

fx=5x5x+5  and f2-x=55x+5

fx+f2-x=1

⇒f120+f220+…+f3920

=f120+f3920+…+f1920+f2120+f2020

=19+12=392

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About this question

This is a previous-year question from JEE Main 2021, 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.