Domain and Range of the functions

[kidia]

Please can anybody help me on this two functions it confuse me because has two and thee variables.

Find the Domain and Range of each of the following functions

a)f(x,x)=\sqrt{\frac{x-y}{x+y}}

b)f(x,y)=\[in{(x^2+y^2+z^2)}

 

[leon1127]

a) x+y not equal to zero and (x-y/x+y)>=0, range should be all positive real

b) i assume that is Ln[x^2+y^2+z^2] then the argument can't be non-positive.

These functions map to one demensional space, so the range should be clear and obvious. Domain is similar to R^1, like postive argument under square root, divid by 0 etc.