JEE Main 2026 — Binomial Theorem Question with Solution
JEE Main 2026 (05 April Shift 1)
Question
If the sum of the coefficients of and in the expansion of , , is zero, then the value of is __________.
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Show full solutionCorrect answer: 21
Correct answer
21
Step-by-step explanation
The general term in the expansion of is given by:
For the coefficient of , we set the exponent to :
For the coefficient of , we set the exponent to :
Notice that .
The sum of the coefficients of and is zero:
Since , we must use the property :
Substituting :
Answer:
For the coefficient of , we set the exponent to :
For the coefficient of , we set the exponent to :
Notice that .
The sum of the coefficients of and is zero:
Since , we must use the property :
Substituting :
Answer:
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This is a previous-year question from JEE Main 2026, 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.