domain and range calculation

[en_pedro]

someone please show me how to solve this..its not like i want u all to solve this function for me, but please show me how to solve this function..

1) z=sqroot x^2+y^2
2) z=sqroot 4x^2+9y^2
3) z=9x^2+y^2
4) z=(x-1)^2+(y+3)^2

 

[tkhunny]

The word "calculation" is somewhat troublesome. It's really more of a "determination".

x is unrestricted. I assume it's Real?

y is unrestricted. I assume it's Real?

x^2 >= 0

y^2 >= 0

x^2 + y^2 >= 0

sqrt(x^2 + y^2) >= 0 You need to believe this one. Do you?

Are we getting anywhere?