Prove that if f: R->R is an even function, then lim x->0 f(x)=L if and only if lim x->0+ f(x)=L.
The Attempt at a Solution
So far I have:
If f is an even function f(x)=f(-x) for x in domain of f.
Then I am trying to apply the limit definitions, but am unsure of how to write the proof from here.