Let f : R → R be a function. (a) Prove that f is continuous on...

Let f : R → R be a function.

(a) Prove that f is continuous on R if and only if, for every open set U ⊆ R, the preimage f −1 (U) = {x ∈ R : f(x) ∈ U} is open.

(b) Use part (a) to prove that if f is continuous on R, its zero set Z(f) = {x ∈ R : f(x) = 0} is closed.

Expert Solution

Colby Messinger answered 11 months ago

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