JEE Main 2019MathematicsSequences and SeriesEasyMCQ

JEE Main 2019 — Sequences and Series Question with Solution

JEE Main 2019 (09 Apr Shift 2)

Question

The sum of the series 1+2×3+3×5+4×7+… upto 11th term is:

Choose an option

Show full solutionCorrect option: C
Correct answer
C946

Step-by-step explanation

Given series is 1+2×3+3×5+4×7+5×9+…

Thus, the general term is Tr=r2r-1

Hence, the sum of 11 terms of the series is S11=∑r=111r2r-1

⇒S11=2∑r2-∑r

Using the formulae for ∑r2r=1n=nn+12n+16 and ∑rr=1n=nn+12, we get

S11=2⋅1111+122+16-1111+12

⇒S11=44×23-66

⇒S11=1012-66=946.

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About this question

This is a previous-year question from JEE Main 2019, 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.