Skip to main content

Let S be the sum of the first 9 term of the series : x+ka+x^2+(k+2)a+x^3+(k+4)a+x^4+(k+6)a+… where a≠ 0 and x≠ 1. If S= x^10-x+45a(x-1) x-1 , then k…

JEE Main 2020 — Mathematics Algebra

2020mcqhard

Let SSS be the sum of the first 999 term of the series :

x+ka+x2+(k+2)a+x3+(k+4)a+x4+(k+6)a+…{x+ka}+{{x}^{2}+(k+2)a}+{{x}^{3}+(k+4)a}+{{x}^{4}+(k+6)a}+\ldotsx+ka+x2+(k+2)a+x3+(k+4)a+x4+(k+6)a+… where a≠0a\neq 0a=0 and x≠1x\neq 1x=1. If S=x10−x+45a(x−1)x−1S=\frac{{x}^{10}-x+45a(x-1)}{x-1}S=x−1x10−x+45a(x−1)​ , then kkk is equal to

Official previous-year question

Held on 2 Sept 2020 · Verified 6 Jul 2026.

Options

  1. A

    −5-5−5

  2. B

    111

  3. C

    −3-3−3

  4. D

    333

Did you get this right?

Sign in to track your attempts and accuracy.

Your note

Sign in to keep a private note on this question. Nothing you write is ever public.

JEE Main Algebra in other years

More JEE Main Algebra questions

Other Mathematics topics for JEE Main

Keep practicing Algebra

Work through every JEE Main Algebra PYQ, year by year.

Browse all Mathematics topics