Yea, but conceptually it's a bit smelly to have f(x) get larger and larger the closer x is to 0 and then suddenly have it be 0 once x reaches 0.
Intuitively nice in a sense but I honestly think '0' is misrepresenting what is going on here. I'm ok with it being ' "+ and/or -" infinity' as a new definition.
Programmatically I think it should result in a NULL or VOID or similar. I mean, by definition it has no definition.