find the absolute maximum and minimum f(x)=x^2+4x; on [-5,5]

Question

find the absolute maximum and minimum  f(x)=x^2+4x; on [-5,5]

anonymous · Answer

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mertsj · Answer

Did you find the vertex of this parabola?

anonymous · Answer

no.. I thought you just had to find the derivative and then plug in for x...

mertsj · Answer

I guess it depends on what chapter you are studying.

anonymous · Answer

haha can you help? :)

mertsj · Answer

The x coordinate of the vertex is -b/2a.   It is in the given interval?

anonymous · Answer

yeah check out my screen shot of the problem

mertsj · Answer

So, to find the minimum, plug the x coordinate of the vertex into the equation and find the y coordinate.  That will be the absolute minimum of the parabola and thus the absolute minimum in the prescribed interval.

anonymous · Answer

yeah i got 16 for the max and -6 for the min but it says its wrong....

mertsj · Answer

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