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    I've been given the equation:

    A=600x-24x^2

    I found dA/dx=-48x+600

    and it says find d^2A/dx^2, which I find to = -48.

    It wants to plug the stationary value (600/48) into it to determine its nature. I can't because there's no x in the second derivative. Any help is greatly appreciated, thanks

    Edit:Title should read I found the second derivitave but I cant do the rest
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    doesn't that mean that the second derivative is -48, which is < 0 and so it is a maximum?
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    When x=(600/48), what is the value of the second derivative? (hint: just state the value, it is independent of x)
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    What do you mean by "determine its nature"?

    Anyhow, just look at it this way: for any given value of x, the slope will be -48. The x quite literally does not matter.
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    What do you mean by "determine its nature"?
    determine whether its a minimum(>0), maximum(<0) or point of inflection(=0)

    and yeah, it says find the value of d^2A/dx^2, so the value being -48, its <0 so its a maximum, Thanks
 
 
 
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Updated: February 11, 2010

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