1. Domain of a function

Find the domain of a function

$\displaystyle f(x,y)=\sqrt{25-x^2-y^2}$

2. Originally Posted by Apprentice123
Find the domain of a function

$\displaystyle f(x,y)=\sqrt{25-x^2-y^2}$
Hint: Are square roots defined for all inputs, or only non-negative ones? What inequality does this suggest for the allowable input values for this function?