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Homework Help: Implicit differentiation

  1. May 30, 2010 #1
    1.
    I'm pretty sure I've got this right.. just needing a check. Cheers!

    2.
    x^2+2xy-y^2+x^2=2

    3.
    2x+2x(dy/dx)+2y-2y(dy/dx)+2x=0
    2x(dy/dx)-2y(dy/dx)=-4x-2y
    dy/dx(2x-2y)=-4x-2y
    dy/dx=(-4x-2y)/(2x-2y)
     
  2. jcsd
  3. May 30, 2010 #2
    Correct, but you can factorise and multiply top and bottom by -1 to become
    [tex]\frac{dy}{dx} = \frac{y+2x}{y-x} [/tex]
    which looks nicer. :smile:
     
    Last edited: May 30, 2010
  4. May 30, 2010 #3
    Thanks for the check.

    Cheers!
     
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