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Homework Help: Level curves?

  1. Jun 26, 2008 #1
    This is a problem I got from a Stanford class in calc 3:

    Let f(x,y,z)=xyz+3. Find an equation of the level surface that passes through the point (1,-2,0).

    This is as far as I have gotten:
    The constant for the level surface will be k = xyz + 3 = (1)(-2)(0) + 3 = 3.
    The equation is thus 3 = xyz + 3, or xyz = 0.
    From this, I understand that the level surface will consist of the coordinate axes, but is there any way to parametrize or otherwise explicitly define this? If not, should xyz = 0 be sufficient as an equation of the level curve? Thanks!
  2. jcsd
  3. Jun 26, 2008 #2
    Well, from what I can tell, the equation xyz=0 seems to be what their looking for.
  4. Jun 26, 2008 #3


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    It doesn't just consist of the coordinate axes (they don't even go through your point), it consists of three planes. Which plane goes through your point?
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