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Math Help - Cal. problem

  1. #1
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    Cal. problem

    Suppose that a point is moving along the path xy=1
    so that
    dy/dt= 3.
    Find dx/dt when x = 1.
    dx/dt =?
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  2. #2
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    dx/dt = dx/dy x dy/dt

    Differentiate xy = 1 implicitly to find dx/dy
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  3. #3
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    Quote Originally Posted by Johnson View Post
    Suppose that a point is moving along the path xy=1
    so that
    dy/dt= 3.
    Find dx/dt when x = 1.
    dx/dt =?
    You need to use a product rule \frac{d}{dt}(xy)=\frac{d}{dt}(1)

    \frac{dx}{dt}y + x\frac{dy}{dt} = 0 (chain rule on the inside because this is with respect to t)

    You are given x = 1 so then (1)(y)=1
    y=1
    substitute all the values in and solve for \frac{dx}{dt} this is part of related rates if you'd like to read in your calculus textbook to clear up any thing you're confused about.
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  4. #4
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    I just want an answer!
    Thanks
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  5. #5
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    Quote Originally Posted by Johnson View Post
    I just want an answer!
    Thanks
    that's not how it works here at MHF ... you need to make an attempt to solve the problem.
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