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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctMediumConceptual

JEE Main 25 February 2021, Shift 1, Maths Q61

Question 61 of 90 in this shift, Maths question 1 of 30, Section A.

Let f,g:N→Nf, g : \mathrm{N} \to \mathrm{N} such that f(n+1)=f(n)+f(1) ∀ n∈Nf(\mathrm{n}+1) = f(\mathrm{n}) + f(1)\ \forall\ \mathrm{n} \in \mathrm{N} and gg be any arbitrary function. Which of the following statements is NOT true ?
  1. (1)If ff is onto, then f(n)=n ∀ n∈Nf(\mathrm{n}) = \mathrm{n}\ \forall\ \mathrm{n} \in \mathrm{N}
  2. (2)ff is one-one
  3. (3)If gg is onto, then fogfog is one-oneOfficial answer
  4. (4)If fogfog is one-one, then gg is one-one

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.