Thread: Multivariable Delta Epsilon Proof

Q: limit of f(x,y)=(x^3-y^3)/(x^2+y^2) as (x,y) -> (0,)?

What I tried:
1. Picked 0 as L
2. We know x^2+y^2 < d^2
3. and lxl=<d and lyl=<d

I can't think of an inequation needed

Any help would be greatly appreciated. Thanks

Originally Posted by 6DOM

Q: limit of f(x,y)=(x^3-y^3)/(x^2+y^2) as (x,y) -> (0,)?

What I tried:
1. Picked 0 as L
2. We know x^2+y^2 < d^2
3. and lxl=<d and lyl=<d

I can't think of an inequation needed

Any help would be greatly appreciated. Thanks

I think you mean inequality. As



try

Originally Posted by Danny

I think you mean inequality. As



try

I'm not sure I understand you.

I thought we needed some kind of inequality that looks like

l(x^3-y^3)/(x^2+y^2)l =<

so that we can set delta

Originally Posted by 6DOM

I'm not sure I understand you.

I thought we needed some kind of inequality that looks like

l(x^3-y^3)/(x^2+y^2)l =<

so that we can set delta

If



then



then