JEE Main 2022 · MathsNumerical answerNumerical valueMediumCalculation

JEE Main 29 July 2022, Shift 1, Maths Q24

Question 24 of 90 in this shift, Maths question 24 of 30, Section B.

Let

a_1, a_2, a_3, \ldots

be an A.P. If

\sum_{r=1}^{\infty} \frac{a_r}{2^r} = 4

, then

4a_2

is equal to __________.

Official answer

NTA final key.

Chapter: Sequences and Series
Topic: Arithmetico-Geometric Series
Idea tested: Sum of Infinite AGP

Same idea in other shifts

Asked 5× in all

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26 Feb 2021, Shift 1 · Q78The sum of the infinite series $1+\frac{2}{3}+\frac{7}{3^2}+\frac{12}{3^3}+\frac{17}{3^4}+\frac{22}{3^5}+\ldots\ldots$ is equal to :EasySingle correct
25 Jul 2021, Shift 1 · Q84If the value of…MediumNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.