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JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 25 February 2021, Shift 2, Maths Q65

Question 65 of 90 in this shift, Maths question 5 of 30, Section A.

A function

f(x)

is given by

f(x) = \frac{5^x}{5^x + 5}

, then the sum of the series

f\left(\frac{1}{20}\right) + f\left(\frac{2}{20}\right) + f\left(\frac{3}{20}\right) + \ldots\ldots + f\left(\frac{39}{20}\right)

is equal to :

(1) $\frac{29}{2}$
(2) $\frac{49}{2}$
(3) $\frac{39}{2}$ Official answer
(4) $\frac{19}{2}$

Official answer

Option 3

NTA final key.

Chapter: Relations and Functions
Topic: No close match in our taxonomy
Idea tested: No close match in our taxonomy

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.