# quick vector calc question

• Sep 21st 2009, 12:56 PM
holly123
quick vector calc question
how would i go about graphing
f(x,y,z)= -1
or any constant for that matter...?
• Sep 21st 2009, 01:24 PM
Calculus26
you can't.

for functions of the form w = f(x,y,z) it takes three dimensions for the domain and would require a 4th dimension for the range which humans can't do.

One way of thinking of this is think of f(x,y,z) as the temperature at any point in 3 space. In your case the temp is -1 everywhere.

You can't visualuze temperature in your 3 -D world can you human?

Actually you can if you add color as with infrared imaging
• Sep 21st 2009, 01:25 PM
holly123
i was thinking it seemed impossible. i'm studying for my first test which is in 20 minutes. i was just wondering thanks for reassuring me
• Sep 21st 2009, 01:27 PM
Calculus26
Elaboration level surfaces
if for example f(x,y,z) = x^2 + y^2 +z^2

then f(x,y,z) = 1 woulde be the level surface

x^2 + y^2 +z^2 = 1

meaning that on a sphere of radius 1 f has the same value at all points.

This is analagous to the level curve for fns of 2 variables
• Sep 21st 2009, 01:30 PM
holly123
thanks! one last quick question..the formula for an elipse. is it x^2/a + y^2/b =1
• Sep 21st 2009, 01:34 PM
Calculus26
yes --if it is centered at the origin