Question

3. Over what interval is the function decreasing?

Answer 1

x∈(-∞; 0).

Explanation:

1) the given function is a parabola with its vertex in (0;0). Then

2) the increasing interval is (0:+∝), decreasing interval is (-∝;0).

Answer 2

The derivative of a function may be used to determine whether the function is increasing or decreasing on any intervals in its domain. If f′(x) > 0 at each point in an interval I, then the function is said to be increasing on I. f′(x) < 0 at each point in an interval I, then the function is said to be decreasing on I.