(a)

Observe the derivative graph:

From the first derivative test if

\"\"

positive on the interval

\"\"

, then the function

\"\"

increases \ \ on the interval

\"\"

The graph

\"\"

is decreasing on

\"\"

since

\"\"

\"\"

The graph $\"\"$ is increasing on $\"\"$ since $\"\"$ on $\"\"$ .

The graph $\"\"$ is again increasing on $\"\"$ since $\"\"$ on $\"\"$ .

$\"\"$

(b)

Use first derivative test to identify all relative extrema.

$\"\"$ changes from negative to positive at $\"\"$ . \ \

Therefore according to first derivative test , the function has minimum at $\"\"$ .

(a) Increasing on

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and

\"\"

Decreasing on

\"\"

(b) Relative minimum at

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