Question

how do i start this proof.
Let f:A-B be a bijection (one-to-one, and onto).
Prove: For every x in A, (f-1 of f)(x) = x.

Answer 1

it is obvious its true, can i just use an example.?

Answer 2

example wont work since you need to prove for every x in A

Answer 3

not sure how does it look like
does it look like this?
\[\forall x \in A : ((f-1)(f))(x) = x\]

Answer 4

\[\it is (f ^{-1} of f)(x)=x which looks like f ^{-1}(f(x))=x\]