JEE Main 2019MathematicsBinomial TheoremMediumMCQ

JEE Main 2019 — Binomial Theorem Question with Solution

JEE Main 2019 (12 Apr Shift 1)

Question

The coefficient of x18 in the product 1+x1-x101+x+x29  is

Choose an option

Show full solutionCorrect option: A
Correct answer
A84

Step-by-step explanation

1+x1-x101+x+x29
=1+x1-x1-x91+x+x29
=1-x21-x1+x+x29
=1-x21-x39
So, Coefficient of x18 in 1+x1-x101+x+x29
= Coefficient of x18 in 1-x21-x39
= Coefficient of x18 in 1-x2C0 9+C1 9-x3+C2-x32+… 9
=C6 9-16=C3 9=9.8.71.2.3=84

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About this question

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