# Delta/Epsilon Proof for General Cases

1. Oct 4, 2009

### ssayan3

Hey guys, this isn't a math problem for homework or for a course, but simply for my own interest... This is one that I couldn't crack back in Analysis but that I'd like to get some help on resolving for my own peace of mind:

Prove f(x,y) = xy is continuous at (x,y) in a domain D$$\subset$$ R. I can do this easily with specific cases of (x,y) but I couldn't ever figure out the general case :-(

Last edited: Oct 4, 2009
2. Oct 4, 2009

### LCKurtz

Try writing xy - ab = (xy - ay) + (ay - ab) and working with that.