# Thread:

1. ## domain of a function

f(x;y) = 1/ (9x^2 + y^2)

what is the domain of this function? i know that 9x^2 + y^2 cannot be equals to 0 so where do i go from there?

2. Originally Posted by yen yen
f(x;y) = 1/ (9x^2 + y^2)

what is the domain of this function? i know that 9x^2 + y^2 cannot be equals to 0 so where do i go from there?
The domain is the set of all ordered pairs (x, y) where $x \in$ R\{0} and $y \in$ R\{0}.

3. hi
$9x^{2}+y^{2}$ cannot equal zero only when $x$ and $y$ aren't equal to zero.
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