# Domain and Range of the functions

1. Apr 15, 2006

### kidia

Please can any body 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)}$$

2. Apr 16, 2006

### 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 arguement cant 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 arguement under square root, divid by 0 etc.