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    ive been given the following function to differentiate and find the turning points.

    z = e^(2x^2-12x-12xy+y^2-4y)

    i do partial differentiation but that only leads to 8x = 7y+ 4 and therefore cant find the stationary point.

    any help much appreciated
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    Show your working? It comes out fine for me.
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    (Original post by Mr M)
    Show your working? It comes out fine for me.
    Zx = (4x-12-12y)e^(2x^2-12x-12xy+y^2-4y)

    Zy = (-12x+2y-4)e^(2x^2-12x-12xy+y^2-4y)

    then i set them equal to each other to find the turning points but get stuck there
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    (Original post by ilikemaths1)
    Zx = (4x-12-12y)e^(2x^2-12x-12xy+y^2-4y)

    Zy = (-12x+2y-4)e^(2x^2-12x-12xy+y^2-4y)

    then i set them equal to each other to find the turning points but get stuck there
    Set them equal to zero not each other?
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    This document will help with this topic.

    http://personal.maths.surrey.ac.uk/s...x_min_2var.pdf
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    (Original post by Mr M)
    This document will help with this topic.

    http://personal.maths.surrey.ac.uk/s...x_min_2var.pdf
    i find the article really helpful, thank you very much
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    (Original post by Mr M)
    This document will help with this topic.

    http://personal.maths.surrey.ac.uk/s...x_min_2var.pdf
    do you get y = -40/34?
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    (Original post by ilikemaths1)
    do you get y = -40/34?
    That cancels down but yes.
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    (Original post by Mr M)
    This document will help with this topic.

    http://personal.maths.surrey.ac.uk/s...x_min_2var.pdf
    Sorry to hijack this thread but do you know any good ways of remembering how to classify stationary points? It seems simple but I can never remember the different conditions for the different types of points.
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    (Original post by james22)
    Sorry to hijack this thread but do you know any good ways of remembering how to classify stationary points? It seems simple but I can never remember the different conditions for the different types of points.
    I just learned them by covering them up and writing them down and then checking I had it right. I can still remember them 25 years later so it must have worked.
 
 
 
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