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Tanget plane of z=ycos(x-y), at point (2,2,2)

  1. Oct 8, 2008 #1
    Find the tanget plane using partial derivatives.

    z=ycos(x-y), at point (2,2,2)


    attempted: fx(x,y)=ysin(x-y)*1
    fx(2,2)=0
    fy(x,y)=1*sin(x-y)*1
    fx(2,2)=0
    z-2=0(x-2)+0(x-2)
    z=2 Incorrect
     
  2. jcsd
  3. Oct 8, 2008 #2

    Hootenanny

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    Welcome to Physics Forums.

    Are you sure about your evaluation of fx and fy?
     
  4. Oct 8, 2008 #3
    no im noy sure i may be finding the partial derivative of both fx and fy wrong
     
  5. Oct 8, 2008 #4

    gabbagabbahey

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    You need to use the product rule to find fy since there is a y both in front of the sin, and in its argument.
     
  6. Oct 8, 2008 #5
    got it thanks
     
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