1. The problem statement, all variables and given/known data Prove the following, using the meaning of a limit: 2. Relevant equations epsilon > 0, delta > 0 0 < sqrt(x^2 + y^2) < delta | f(x) - 0 | < epsilon (1) 3. The attempt at a solution So, I know that I have to elaborate on the inequality in (1), further. However, I'm not sure of how to go about this. If I start transposing it seems to get much too messy and I end up with a proposed delta which seems far too complex. Is there some simplification that I'm overlooking here? Any help is really appreciated, ta.