JEE Main 2026 — Sequences and Series Question with Solution
JEE Main 2026 (02 April Shift 1)
Question
If , then is equal to _______.
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Show full solutionCorrect answer: 91
Correct answer
91
Step-by-step explanation
Given .
Let . The -th term of the sequence is given by .
Replacing with and , we get:
Now, find the difference :
Substitute this into the given summation:
Using the formula for the sum of squares of the first natural numbers, :
Answer:
Let . The -th term of the sequence is given by .
Replacing with and , we get:
Now, find the difference :
Substitute this into the given summation:
Using the formula for the sum of squares of the first natural numbers, :
Answer:
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This is a previous-year question from JEE Main 2026, covering the Sequences and Series 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.