The average rate of change of a function relates to a function when it is

increasing, decreasing, and constant on an interval.

Draw the example graphs for three situations.

Observe the graph:

The function is increasing along an interval, the average rate of change is positive.

Observe the graph:

The function is decreasing along an interval, the average rate of change is negative.

Observe the graph:

The function is constant along an interval, the average rate of change is zero.

When a function is increasing on an interval, the average rate of change is

positive. When a function is decreasing on an interval, the average rate of change

is negative. When a function is constant on an interval, the average rate

of change is zero.

When a function is increasing on an interval, the average rate of change is

positive. When a function is decreasing on an interval, the average rate of change

is negative. When a function is constant on an interval, the average rate

of change is zero.