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Homework Help: Finding Cartesian equation of parametric surface.

  1. Oct 8, 2009 #1

    Ral

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    1. The problem statement, all variables and given/known data
    Find the Cartesian equation of the parametric surface: [2cos(t)cos(s), 3sin(s), sin(t)cos(s)]

    Find eqn. of the tangent plane when S = 0, t = pi/2


    2. Relevant equations



    3. The attempt at a solution

    I'm not quite sure what to do. All I've done is squared each term, which gave me.

    [tex]4cos^2(t)cos^2(s)[/tex]
    [tex]9sin^2(s)[/tex]
    [tex]sin^2(t)cos^2(t)[/tex]
     
  2. jcsd
  3. Oct 8, 2009 #2
    [tex]x=2\cos t\cos s[/tex]

    [tex]y=3\sin s[/tex]

    [tex]z=\sin t \cos s[/tex]

    Can't you find [tex]\alpha[/tex] and [tex]\beta [/tex] so that [tex]x^2+\alpha y^2 + \beta z^2= constant[/tex]?
     
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