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Homework Help: Answer check please

  1. Mar 8, 2005 #1
    If anyone could check this answer for me, it would be greatly appreciated.

    Find the equations relating the differentials on the curve [tex] 9y^2= x^3 +3x^2 [/tex] at the points [tex] (1,\frac{2}{3}), (-2,\frac{2}{3}), (-3,0) [/tex]

    Here's what I got:

    [tex] y'= \frac {x^2+2x}{6y} [/tex]

    [tex] m @ (1,\frac{2}{3})= \frac {3}{4} [/tex]
    equation: 9x-12y-1=0

    [tex] m @ (-2,\frac{2}{3})=0 [/tex]
    equation: y= 2/3

    [tex] m @ (-3,0) [/tex]
    does not exist

    Thanks in advance.
  2. jcsd
  3. Mar 8, 2005 #2


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    Science Advisor

    Everything appears correct except the last item.

  4. Mar 8, 2005 #3
    Thanks for the help.
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