Your answer of 6 is correct!
Then why do you just list 3?
Let A = {1,2,3}
(a) How many one-to-one functions are there from A to A?
(b) List all one-to-one functions onto A?
So far I have this:
(a) I believe the answer is 6, NOT SURE.
(b)
f1: A A
1 to 1
2 to 2
3 to 3
f2: A A
1 to 2
2 to 3
3 to 1
f3: A A
1 to 3
2 to 1
3 to 2
NOT SURE IF I ANM RIGHT? ANY HELP WOULD BE GREAT. THANK YOU!