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Math Help - year 13 differentiation - please help me

  1. #1
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    year 13 differentiation - please help me

    find the values of t when the function defined by
    X=4t^3 and y=3t^2-7t is concave up.
    give and derivative you need to find when solving this problem .
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  2. #2
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    Re: year 13 differentiation - please help me

    Differentiate twice with respect to x, as directed here: Parametric derivative - Wikipedia, the free encyclopedia.

    Set the second derivative greater than zero and solve for values of t.
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  3. #3
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    Re: year 13 differentiation - please help me

    Quote Originally Posted by Damini View Post
    find the values of t when the function defined by
    X=4t^3 and y=3t^2-7t is concave up.
    give and derivative you need to find when solving this problem .
    dx/dt=12t^2 dy/dt=6t-7 So dy/dx=(6t-7)/12t^2
    Get 2nd derivative using d/dx(dy/dx)=d/dt(dy/dx)*dt/dx
    For concave up you want 2nd derivative >0
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