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Math Help - partial derivatives

  1. #1
    Junior Member
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    partial derivatives

    I have the following equation:

    z (x y)= 200 + 1/100(x^2 - 4xy + 3y^2)
    I need to find the partial derivatives in order to find grad z.

    After expanding the brackets out I got the partial derivatives as:

    dz/dx = (1/50x - 1/25y)

    dz/dy = (1/25x + 3/50y)

    Thus giving me grad z as:

    (1/50x - 1/25y) + (1/25x + 3/50y)

    Is this right?
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  2. #2
    MHF Contributor kalagota's Avatar
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    Taguig City, Philippines
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    Quote Originally Posted by iwishiunderstood View Post
    I have the following equation:

    z (x y)= 200 + 1/100(x^2 - 4xy + 3y^2)
    I need to find the partial derivatives in order to find grad z.

    After expanding the brackets out I got the partial derivatives as:

    dz/dx = (1/50x - 1/25y)

    dz/dy = (1/25x + 3/50y)

    Thus giving me grad z as:

    (1/50x - 1/25y) + (1/25x + 3/50y)

    Is this right?
    that should be negative
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  3. #3
    Junior Member
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    stupid me !!!!


    cheers for the reply appreciated!!
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