Question

9. Let A be a finite set. If f: A+A is an onto mapping, show
that it is one-one also.​

Answer 1

Answer:

A be a finite set

f:A→ A is onto that means every element in Y set has a preimage in X set

That also means that every element in

X must have only one image in Y because both X,Y are equal

so the function is one - one also.

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