1. The problem statement, all variables and given/known data I don't remember the exact question right now, but it was something like this: f(x) = sqrt(4 - x^2) I needed to give the domain / range of it, and also symmetry I believe. 2. Relevant equations 3. The attempt at a solution I know this is a half circle after being graphed, but how can I show the domain and range in a math way? For domain, I know 4 - x^ must >= 0, so I can solve for it that way. But what about range? Can I also just isolate x and then get sqrt with y inside and restrict to real numbers?