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JEE Main 2021 · MathsNumerical answerNumerical valueMediumCalculation

JEE Main 25 July 2021, Shift 1, Maths Q84

Question 84 of 90 in this shift, Maths question 24 of 30, Section B.

If the value of

\left(1+\frac{2}{3}+\frac{6}{3^2}+\frac{10}{3^3}+\ldots\ \text{upto}\ \infty\right)^{\log_{(0.25)}\left(\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+\ldots\ \text{upto}\ \infty\right)}

is

l

, then

l^2

is equal to _________.

Official answer

3

NTA final key.

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

Same idea in other shifts

Asked 2× in all

3 Apr 2025, Shift 2 · Q8If the probability that the random variable $X$ takes the value $x$ is given by $P(X = x) = k(x + 1)3^{-x},\ x = 0, 1, 2, 3\ldots$ , where…MediumSingle correct

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 42 of the 174 JEE Main shifts held from 2017 to 2026.