[CAS] find domain for function?

[Aries]

Not all functions are invertible in their domain, y=x^2 is non-invertible in its domain.
What if f(x) is non-invertible ?
A function f is invertible if and only if it's injective, that is whenever f(x)=f(y), x=y.
In certain cases restricting domain of f(x) could make it invertible.
Best,

Aries