JEE Main 2021 · MathsMultiple choiceSingle correctHardMulti-step

JEE Main 27 August 2021, Shift 1, Maths Q78

Question 78 of 90 in this shift, Maths question 18 of 30, Section A.

0<x<1

, then

\frac{3}{2}x^2+\frac{5}{3}x^3+\frac{7}{4}x^4+\dots

, is equal to :

(1) $x\left(\frac{1+x}{1-x}\right)+\log_e(1-x)$ Official answer
(2) $\frac{1+x}{1-x}+\log_e(1-x)$
(3) $x\left(\frac{1-x}{1+x}\right)+\log_e(1-x)$
(4) $\frac{1-x}{1+x}+\log_e(1-x)$

Official answer

Option 1

NTA final key.

Chapter: Sequences and Series
Topic: Arithmetico-Geometric Series
Idea tested: Integration Method for Harmonic-Geometric Series

Same topic in other shifts

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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.