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# Can't find second derivative watch

1. 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
2. doesn't that mean that the second derivative is -48, which is < 0 and so it is a maximum?
3. When x=(600/48), what is the value of the second derivative? (hint: just state the value, it is independent of x)
4. 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.
5. 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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