Interval
Sign of
f
\(^\prime (x)\)
Conclusion
\((-\infty ,0)\)
negative
\(f\) is decreasing on \((-\infty ,0)\)
(0,2)
negative
\(f\) is decreasing on \((0,2)\)
\((2,\infty )\)
positive
\(f\) is increasing on \((2,\infty)\)