25: The domain is D( f ) = ℝ.
The second derivative is

Dividing points: The equation f ′′(x) = 0 has solutions x = −1 and x = 1.
There are no points in D( f ) where the second derivative does not exist.

Intervals of concavity will be (−∞,−1], [−1,1], and [1,∞). Determine concavity and points of inflection using a chart.

Next hint
Answer