10: Derivative is

Critical points: f = 0 for x equal to plus or minus root of 2; there are no points in D( f ) where f ′ does not exist.

Local maximum f at root of 2 with value 2; local minimum f at minus root of 2 with value −2.

Remark: One-sided derivatives at endpoints ate

Now determine concavity using f ′′.

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