it's always included in C, that's all we can say. Exemple f R-R x|-> x², and C is [-4,4], we have f(f^-1(C))=[0,4] =/= C
I have a following problem to solve:
For some function and I have to find something, that would equal .
I managed to show that and I have a counterexample that disproves . Yet I have no idea what could equal to.