Peer Review

Quadratic Functions

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Overall Rating:

Content Quality:

Effectiveness:

Ease of Use:

Overview:: This learning activity allows the student to explore how the parameters of a
quadratic relate to its graph. It also compares the quadratic in standard form
with the quadratic in general form.
Type of Material:: Simulation
Recommended Uses:: Classroom demo; student exploration
Technical Requirements:: JAVA enabled browser
Identify Major Learning Goals:: The successful student will learn about the relationship between a quadratic
function and the graph.
Target Student Population:: Intermediate algebra and Precalculus students
Prerequisite Knowledge or Skills:: The activities assume no prior knowledge other than the Cartesian coordinate
system.

Rating:
Strengths:: This learning object consists of a graphing tool accompanied by four activities.
On the left is a frame containing well written instructions that guide the
student through the activities. The frames width can easily be resized. On
the right is the graphing tool. In the activities, the student is asked to
enter the graph of y = a*x^2+b*x+c and is instructed to change the parameters
a, b, and c to explore the effect on the graph. The parameters can be inputted,
incremented manually, or automatically so that the student can explore the
effect on the graph when the parameters change. Instead of telling the student
what to do, the activities ask to students to explore on their own. The
concepts become more advanced as the student uses completing the square to
investigate the relationship between the parameters and the graphs.
Concerns:: Reformatting the left activity frame to use bulleting, numbering, or some other
organizational technique would make the instructions easier to follow.

Rating:
Strengths:: The object can be used by students learning on their own without the assistance
of an instructor. The student using this activity will have the opportunity to
explore the graphs of quadratics without getting frustrated. Completion of this
activity requires the student to manipulate formulas on paper and experiment
extensively with the results to investigate the more advanced concepts of
quadratic functions and their graphs.
Concerns:: The variable w has multiple uses in the applet; this can be confusing to the
user. The w is used as a view dimension, and in the activity directions to Plot
(x-v)*(x-w). The animation controls also use a double v, which appears on the
screen as a w.

The animation can be extremely quick, depending on the users computer. An
additional comment that using a value of E that is negative will produce a
slower graph would be helpful to the student who does not realize this in
advance.

The text does not provide a summary of the concepts so that the user is unable
to benchmark his/her own conclusion with the concept being investigated.

Rating:
Strengths:: The instructions for each of the activities are easy to follow. If the student
follows the directions then there should be no difficulties in using this
learning object. A help link that gives explanations on how to use the graphing
tool is provided.
Concerns:: It is very difficult to distinguish two equations that have the same graph using
different colors for the graph. The applet does not toggle between the two
colors, leaving the user to wonder if the second graph is on the screen.
Instead the applet assigns one color to both equations, regardless of the
instructions given by the user. To observe the second color, the user must
delete the function that controlled the first color.

The requirement of using * to indicate multiplication is cumbersome since most
graphing utilities now use syntax with implied multiplication. The parameter
controls for animation could be enlarged and separated so that they do not
overlap. It would be helpful to have the Stop button also present for the
expanded animation controls.