Question:
If functions f: A → B and g: B → A satisfy g o f = IA, then show that f is one-one and g is onto.
Solution:
Given,
f: A → B and g: B → A satisfy g o f = IA
It’s clearly seen that function ‘g’ is inverse of ‘f’.
So, ‘f’ has to be one-one and onto.
Hence, ‘g’ is also one-one and onto.