well-defifined functions

Question

Are the following well-defifined functions (i.e. satisfy the conditions of the defifinition)?

(a) f :R → R, f(x) = 1/ x+2

(b) g :N → Z, g(x) = (−1)^x

(c) h: N → N, h(x) = x − 1.

Answer 1

no

yes

yes

f(-2)=1/(-2+2)=1/0 = undefined