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Math Help - need help with derivative

  1. #1
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    need help with derivative

    Find dy/dx at point (1,2) if y^3 sqrt(x)-3x^2y=2.
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by gracy View Post
    Find dy/dx at point (1,2) if y^3 sqrt(x)-3x^2y=2.
    Implicit differentiation:

    d/dx[y^3 sqrt(x) -3 x^2 y = 0]

    so:

    3 y^2 dy/dx sqrt(x) + y^3 (1/2)/sqrt(x) - 3 x^2 dy/dx = 0

    so:

    dy/dx [3 y^2 sqrt(x) - 3 x^2] +y^3/(2 sqrt(x)) = 0

    and Bob's your uncle.

    RonL
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