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Homework Help: Check request: Implicit Differentiation

  1. Oct 14, 2008 #1
    1. The problem statement, all variables and given/known data
    Find the value of dy/dx at x=2 when

    x2+xy=5

    3. The attempt at a solution

    To find y:
    22+2y=5
    y=1/2

    To find dy/dx:
    2x(dx/dx)+x(dy/dx)+y(dx/dx)=0

    2x+x(dy/dx)+y=0

    (dy/dx)=(-2x-y) / x

    Plug in y and x:
    dy/dx=-2(2)-(1/2) / 2

    dy/dx=-9/4 when x=2
     
  2. jcsd
  3. Oct 14, 2008 #2

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Correct.
     
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