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Math Help - Differentiation Problem

  1. #1
    Junior Member
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    Differentiation Problem

    If y = 3x^3 + 2x and dx/dt = 5, then find dy/dt when x = 2:

    My work:

    y = 3x^3 +2x

    dy/dt = 9x^2(dx/dt) + 2

    dy/dt = 9(4)(5) + 5

    dy/dt = 182

    What did I do wrong here?
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  2. #2
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    Quote Originally Posted by Maziana View Post
    If y = 3x^3 + 2x and dx/dt = 5, then find dy/dt when x = 2:

    My work:

    y = 3x^3 +2x

    dy/dt = 9x^2(dx/dt) + 2(dx/dt)
    ...
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