The Department of Mathematics Education

J. Wilson, EMAT 6680


EMAT 6680 Assignment 2


Last modified July 5, 2008
Explore ALL of Assignment 2. Then, select one problem from Assignment 2 and prepare a Write-up.


1. Construct graphs for the parabola

for different values of a, b, and c. (a, b, c can be any rational numbers).


2. Fix two of the values for a, b, and c. Make at least 5 graphs on the same axes as you vary the third value. For example,



3. Adjust the ranges on the axes in Problem 2 to produce graphs that can be read, interpreted, and used for demonstration.


4. Interpret your graphs. What happens to

(i.e., the case where b=1 and c=2) as a is varied? Is there a common point to all graphs? What is it? What is the significance of the graph where a = 0? Do similar interpretations for other sets of graphs. How does the shape change? How does the position change?



5. For demonstration, is it better to graph 5 graphs at once or produce them in sequence adding one at a time? What are the pedagogical implications of this observation?



6. Graph the parabola



7. Try several graphs of

on the same axes. (i.e., use different values of a)



8. Produce several ( 5 to 10) graphs of

on the same axes using different values for d. Does varying d change the shape of the graph? the position?



9. Graph

Now, on the same axes graph

Describe the new graph. Change the range on the y-axis from -25 to 25 and redraw. Now interpret. What do you think will happen if we change the coefficients of the xy term?

Systematically try different coefficients for the xy term. Are they always the same types of curves?

What about coefficients which are close to zero?

How does the sign of the coefficient change the graph?



10. Graph

Now, on the same axes, graph

Describe the new graph. Try different coeffcients for the xy term. What kinds of graphs do you generate? What coefficients mark the boundaries between the different types of graphs? How do we know these are the boundaries? Describe what happens to the graph when the coefficient of the xy term is close to the boundaries.

Did your find this?

Or,what about this?

Or,
try this one.


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