Multivariable limits with CAS

[springo]

1. The problem statement, all variables and given/known data
I would like to be able to compute multivariable limits with a CAS. I have Mathematica, Derive and an HP 50g.
For example, how would I compute:
\lim_{(x,y)\rightarrow(0,0)}\frac{x^2}{y}

2. Relevant equations

3. The attempt at a solution
On Mathematica I tried:
Limit[x^2/y, {x, y} -> {0, 0}] (doesn't work)
Limit[x^2/y /. {y -> f[x]}, x -> 0] (I think this could work, but I need to figure out what f[x] has to be)

Thanks for your help.

[yyat]

The limit in your example does not exist (it is undefined), because it depends on how you approach (0,0). For example, f(t,t)->0 as t->0 from the right, but f(sqrt(t),t)->1 as t->0 from the right.

[springo]

The limit in your example does not exist (it is undefined), because it depends on how you approach (0,0). For example, f(t,t)->0 as t->0 from the right, but f(sqrt(t),t)->1 as t->0 from the right.
OK, sorry for choosing a wrong example, I'm just starting multivariable calculus. Anyway for existing limits, is there any way to compute them using a CAS?

[gabbagabbahey]

Here's a nice little example using mathematica (http://books.google.ca/books?id=kQmWXy5mbe4C&pg=PA222&lpg=PA222&dq=multivariable+limits,+mathematica&source=bl&ots=rb7yC7gE3Y&sig=nRZsygcQ-rSi8XBgK3L5UDGa5U8&hl=en&ei=rWm9Saq6GZmQsQOvo5CeAg&sa=X&oi=book_result&resnum=5&ct=result#PPA222,M1). Contour Plots are typically a good way to infer whether a limit exists before you go ahead and calculate it.