Created on: June 11, 2009

Website Address: https://www.curriki.org/oer/Graphing-Equations-Using-TI-82-or-TI-83-Calculators

**Learning Objectives:**

1. Students will be able to accurately graph linear equations on the TI-82 or TI-83+ calculator.

2. Students will be able to successfully capture "screenshots" using the TI-Connect software and save these screenshots, as well as print them.

**Materials:**

Individual students' or classroom set of TI-82 or TI-83+ graphing calculators

TI-Connect software loaded on a classroom computer attached to a printer (if possible)

Students' final draft of their cost curves

**Procedures:**

In this lesson, you will be presenting the basic linear graphing functionalities of the TI-82 or TI-83+ claculator to the students. It is important that each student have their own calculator. If they don't, they can share, but this will certainly slow the process.

Begin the class by having the students practicing transforming the following equations into slope-intercept form. They may work with their groups or partners:

*3x + 2y = 12*

*2y = 15x - 4*

*y - 4 = -3/4 (x + 2)*

*y = 4*

*x = -3*

(The final equation is a trick question -- there is no way to transform this into slope-intercept form!)

Remind students that it is always possible to transform an equation into slope-intercept form, so long as their is a y-variable present. Next, have them turn on their calculators and spend a couple of minutes showing them how to input fractions as division problems enclosed within parantheses -- that is 1/3 becomes (1 / 3) in the syntax of the calculator. Highlight the difference in accuracy between entering 1/3 and 0.3333 (one is a repeating decimal and the other is terminating).

Next, have the students graph the following equation:

*y = 2x + 4*

Explore the graph window with them. Focus particular attention on the "Window" button and the various maximum, minimum, and scale settings (these will be **very** important when it comes to graphing their cost curves!). Allow them to explore what happens when these settings are changed and have them verbalize what these changes signify (that is, why does the graph look almost flat if I keep the x-max and min the same, but change the y-max and min to -100 and 100 respectively? Has the slope **really** changed, or does it just **look** flatter? Why is that?) Also make sure to highlight the "ZStandard" functionality in the "Zoom" menu, as it resets the window to a standard scale. Also highlight the fact that the calculator only graphs equations in slope-intercept form. That is, if they have an equation in another form, they will need to transform it on their own before entering it into the calculator.

Now, have the students graph the equations they transformed at the beginning of the class period. Allow time for every student to graph every equation. Make sure they understand that if they enter all of the equations simultaneously, then the calculator will graph them simultaneously.

After students have become comfortable with the graphing and scale functions of the calculator, briefly introduce them to the TI-Connect software and show them how to capture a screenshot from their calculator and save it to a specified folder on the computer. From there, demonstrate how to print out the screenshot.

Finally, have students get their cost curve final drafts and graph them using the calculator. Remind them that they will need to pay particular attention to the scale and size of the window. (For instance, do they even need to see Quadrants II, III, and IV on the coordinate plane? Why not?) Once students have checked out their graph with you, have them capture the screen shot, save it to the folder, and print it out for their portfolio. Remind them that this is a necessary part of their portfolio for their final grade.