a Mark the interval on the parabola and see which end is positioned higher.
B
b Mark the interval on the parabola and see which end is positioned higher.
C
c Mark the interval on the parabola and see which end is positioned higher.
D
d Mark the interval on the parabola and see which end is positioned higher.
A
a Positive
B
b Negative
C
c Negative
D
d Zero
Practice makes perfect
a Let's mark the given interval 0≤ x≤ 2 on the parabola.
We can see that the left end lies below the right end. Therefore the average rate of change of the parabola over the given interval is positive.
b Let's mark the given interval 2≤ x≤ 5 on the parabola.
We can see that the left end lies above the right end. Therefore the average rate of change of the parabola over the given interval is negative.
c Let's mark the given interval 2≤ x≤ 4 on the parabola.
We can see that the left end lies above the right end. Therefore the average rate of change of the parabola over the given interval is negative.
d Let's mark the given interval 0≤ x≤ 4 on the parabola.
We can see that the left end lies at the same level as the right end. Therefore the average rate of change of the parabola over the given interval is equal to zero.
