Question

Question #fd964

Answer 1

The domain of this expression/function is

`A = {x,yinRR | x^2 + y^2 < 9}`

Explanation:

For the natural logarithm to be defined, what's inside of it must be positive. So, in order for `lna` to exist, `a > 0` must be true.

`9-x^2-y^2 > 0 => x^2 + y^2 < 9`.