# How do I find the relative extrema of this function?

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#f(x)# =#-x^4# +#2x^3# +#8x#

I know that I am looking for the derivative of this function, which I figured out, but I get lost when I set the derivative to zero since I'm dealing with a cubic polynomial. Thank you for helping!

I know that I am looking for the derivative of this function, which I figured out, but I get lost when I set the derivative to zero since I'm dealing with a cubic polynomial. Thank you for helping!

##### 1 Answer

Jul 18, 2018

See the answer below: