Find the interval in which is increasing or decreasing ?

we have

Critical points

⇒x = 0, –1

Clearly,f'(x) > 0 if x>0

And f'(x) < 0 if –1 < x < 0 or x < –1

Hence, f(x) increases in (0,), decreases in (–, –1) U (–1, 0)