After doing a quick review of what they already know about quadratic equations and the graphing calculator we will then point out how graphing a quadratic is the same steps on the calculator as graphing a linear equation

Frank, Kristen

English

The College at Brockport, State University of New York: Digital Commons @Brockport

The College at Brockport: State University of New York
Digital Commons @Brockport
Lesson Plans CMST Institute
10-29-2004
Graphing Quadratic Equations Using the TI
Calculator
Kristen Frank
The College at Brockport
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Frank, Kristen, "Graphing Quadratic Equations Using the TI Calculator" (2004). Lesson Plans. 232.
http://digitalcommons.brockport.edu/cmst_lessonplans/232
Kristen Frank 
TI Technologies 
 
 I will begin the class on graphing quadratic equations using the TI-83 plus 
graphing calculator by reviewing what they know about graphing quadratic equations and 
what they remember about graphing any kind of graph on the TI-83.  We will review this 
using the overhead projector, creating two columns one that is labeled quadratic 
equations and the other that is labeled TI-83 graphing.  In about 6-8 minutes the students 
will raise their hands and tell me everything they know about either one of these.     
 After that we will go over the definition and examples of what a quadratic 
equation is and how we know longer have to spend 20 minutes graphing it by hand we 
can now graph it in relatively 5 minutes by using the TI-83 plus.  For about 5 minutes we 
will write down on the overhead step by step what buttons to press to graph an equation 
while I point the buttons out on the big poster of the calculator hanging in the front of the 
class room.  The students will be following along with the steps on their own calculators.  
We will first review how to graph a linear equation on the graphing calculator since they 
have already done this. First they will tell me to go to y = and type in equation y = 3x + 4. 
Then take a quick look at the graph by hitting the graph button.  Seeing that it is a straight 
line we will then go to 2nd graph and take a look at our chart. Reviewing that the chart is 
where we get our points that we need to plot in order to get the graph we just saw on the 
previous screen.    
 After doing a quick review of what they already know about quadratic equations 
and the graphing calculator we will then point out how graphing a quadratic is the same 
steps on the calculator as graphing a linear equation.  We will then go back to y= and 
clear it out, we will put in x² + 2x + 4 and then go to graph and see that a quadratic is a u 
shaped figure.  The next step will be to go to 2nd graph and look at the chart.  Using paper 
with half of it blank and the other half graph paper with a x-axis and y-axis I will have 
the students copy down the exact chart from -4 to 2 on the blank side of the paper as it is 
on the calculator, I will begin showing them how to do this on the board and I will walk 
around the room to ensure that the class is doing the same.  On the other side of the paper 
I will have the students plot their points and compare what they have drawn with the 
graph on the calculator. The time of this activity will differ depending on how well the 
students are doing but it should only take about ten minutes.   
 Now that the students have the basics of how to graph a quadratic equation on the 
calculator we can explore the equation more.  What happens when we change the c in 
y=ax² + bx + c  (raise the graph up or down), what happens if we change the x² from a 
positive to a negative(smiley to a frown) and what happens if the b is changed(moves the 
graph left or right).  Graphing quadratics is very important on exams so we will spend 
quite a few days graphing quadratics and making sure that the students know they must 
write down the x and y chart before plotting those exact points on their graph paper, they 
must label their graphs and write down everything they know about the graph. 
 
 
 
 
 
1)  y = 
      
 
2) x² + 2x + 4   
                    
                                            
3) graph – last of the top five buttons 
 
 
4) 2nd graph – chart of the x and y values for the graph y = x² + 2x + 4 
 
 
 
Rubric                                                      
1) Could they find y= and                                     1                2                   3                  4 
    type in their equation                                            
2) Did they find their chart and                             1                2                   3                  4 
    write down x and y columns 
3) Did they plot all their points correctly             1                 2                     3                  4 
4) Did they label their graph and                          1                 2                     3                  4 
    answer all questions.          
 
 
 


Graphing Quadratic Equations Using the TI Calculator

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Graphing Quadratic Equations Using the TI Calculator

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