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Implicit differentiation question?

  1. Apr 15, 2012 #1
    1. The problem statement, all variables and given/known data
    use implicit differentiation to find an equation of the tangent line to the curve a the given point.

    y^2(y^2-4) = x^2(x^2-5)

    at (0,-2)


    2. Relevant equations


    y^2(y^2-4) = x^2(x^2-5)


    3. The attempt at a solution

    I got dy/dx to be (3x^2-10x)/(4y^3-8y)

    but the answer book says otherwise:
    (4x^3-10x)/(4y^3-8y)

    while it works out with the point since 0/anything = 0 (which is the answer of what the slope it at that point) i ended up getting the wrong formula in the first place - how is one to do this question then?
     
  2. jcsd
  3. Apr 15, 2012 #2

    LCKurtz

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    So it is telling you exactly where your mistake is. What to you get when you differentiate the ##x^4-5x^2## on the right side?
     
  4. Apr 15, 2012 #3
    good grief i had x^2(x-5) copied on my paper. goodness, nevermind haha. :$$
     
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