Graphing on the TI-83 Plus - GHAEA

1 Graphing on the TI-83 Plus Linear Equations and Inequalities To graph equations on the TI-83 Plus you must first put the equations in slope -intercept form. y = mx + b. Here of course, the m represents the slope of the line and the b represents the y-intercept. To enter an equation into the Graphing mode you would: 1. Turn on the calculator 2. Press the [y =] key in the upper row 3. To enter an equation y = 3x + 3, you would press [3], [x,t,o,n], [+], and [3]. 4. To graph this equation you would press the [graph] key in the upper row. 5. This should display your graph in a normal view. If you want to insure a normal view hit [zoom], [6]. This will make your window a 10x10 graph. (The danger here is that a 10x10 window may not be large enough to view some graphs.)

2 , if the y-intercept is larger than 10 or smaller than -10. You would then have to go to the [window] command and set your boundaries accordingly.) When I talk slope with the students I like to tweak my Graphing capabilities a little by talking about the rolling ball . If the ball is rolling on level ground, the slope is zero. If the ball is rolling up hill, the slope is positive. If the ball is rolling downhill, the slope is negative. After doing this, you can talk about the difference between a zero slope and NO slope . You can get the rolling ball effect by doing 1-3 from above and the adding this to the process. 3b. Move your cursor using the left arrow to the left of Y1. ( , put your cursor over the [\] symbol.

3 3c. Hit the [enter] key four times until you get this symbol (-o) Now go to step 4 above. Have the students watch the ball and talk about the slope of the rolling Up is positive, Down is negative, level is zero. You can also repeat steps 3b and 3c above and get other options such as shading above the line , below the line , dotted lines, etc. That would lead the discussion into the Graphing of linear inequalities. If students want to see the points used to graph the equation and the graph at the same Go to [mode], arrow down to the bottom of the display to the line that starts with [full], arrow over to [G-T] and hit [enter]. Now hit graph and you will see both the graph and the table. To get back to normal, just go back to [mode] and highlight the [Full] and hit [enter].

4 Here is a work sheet to be used with the Graphing of linear equations. Put the following equations into slope intercept form and identify the slope and the y-intercept. (Hint: slope -intercept form is y = mx + b) 1. y = 3x + 4 slope _____ y-intercept _____ 2. -2x + 6 = y slope _____ y-intercept _____ 3. 7 = y slope _____ y-intercept _____ 4. 2y - 6x = 10 slope _____ y-intercept _____ 5. 4x + 3y = 12 slope _____ y-intercept _____ From what we know about slopes and y-intercepts, explain in a paragraph, what each of these graphs would look like. You should have at least one paragraph for each problem. Paint me a visual picture with your words. Graph each of these equations on the provided graph paper. 6. y = 1x + 3 7.

5 Y = (-2/3)x -4 8. y = (3/4)x 9. y = -3 10. y = -3x + 2 11. 2x + 7 = 2y Check your results using the Graphing calculator. Why was number 11 more difficult than the others and what did you have to do to it before you could graph it? Why? Think about If you were asked to graph y > 2x + 3, what do you think it would look like and why? Be ready to talk about your answer. Do you think we could graph this one on the Graphing calculator? Hope this helps! Ron