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CUET · MATHS · PYQ PAPER 2023

The number of all onto functions from the set \(\{1,2, \ldots, n\}\) to itself is

  1. A \(2^n\)
  2. B \(n^2\)
  3. C \(n!\)
  4. D \((2 n)!\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(n!\)

Step-by-step Solution

Detailed explanation

For a function from {1,2,…,n} to itself to be onto, every element must have exactly one pre-image.Since domain and codomain have equal size, onto ⇒ one-to-one (bijection).Number of such functions = permutations of n elements = n!. (C) n!