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Homework Help: Two questions about rotation of this line

  1. Aug 28, 2011 #1
    Two questions about rotation of this "line"

    1. The problem statement, all variables and given/known data

    [tex]3x^2 - 2\sqrt{3}xy +y^2 = 1[/tex]

    2. Relevant equations

    [tex]x = x'\cos\alpha - y'\sin\alpha[/tex]
    [tex]y = x'\sin\alpha + y'\cos\alpha[/tex]

    3. The attempt at a solution

    The discriminant test is

    [tex]4(3) - 4(3)(1) = 0[/tex]

    Supposed to be a parabola, instead we get lines.

    One other thing

    Supposed that in

    [tex]cot2\alpha = \frac{A - C}{B}[/tex]

    And then we get that [tex]\alpha < 0[/tex], can that happen? Can we rotate clockwise?
  2. jcsd
  3. Aug 28, 2011 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Re: Two questions about rotation of this "line"

    The OP is missing a problem statement. What is it that you are having problems with?
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