TI-83 Plus
TI-83 Plus: ........................................................................................................................................................ 1
Plot points: ........................................................................................................................................................ 2
Graphing a function: ......................................................................................................................................... 2
Window:............................................................................................................................................................ 2
Zoom: ................................................................................................................................................................ 3
Trace: ................................................................................................................................................................ 4
Finding the intersection of two curves: ............................................................................................................. 4
Finding a Maximum (or minimum): ................................................................................................................. 4
Absolute Value Functions: ................................................................................................................................ 4
Piecewise Defined functions: ............................................................................................................................ 5
Finding a solution/zero of an equation graphically: ......................................................................................... 5
Evaluating an equation for a given x- value:. ................................................................................................... 5
Regression – Fitting a Function to a set of points:............................................................................................ 6
TI-83 Plus
Basnayake
Page 1 of 6
Plot points:
Steps
Key strokes
1. Enter the (x, y) pairs
STAT  1:EDIT…  ENTER
Type the x and y values under L1 and L2
2. Turn Plot on
2nd Y=  1:Plot 1…  Make sure cursor is over "On" and hit enter
3. Graph
Note: You can change the type of graph at this stage as well by moving the
cursor over the various types next to the heading "Type:" on the screen.
Observe also that Xlist is L1 and Ylist is L2.
GRAPH
Possible problems:
 Don’t see a graph?
ZOOM  9:ZoomStat
Graphing a function:
Steps
How to do it
1. Enter the equation
Y=  Enter the equation next to Y1=. If you want to plot
multiple equations enter one per line. Use the X,T,Θ,n key
to access the variable "x". Use "^" to raise to a power.
GRAPH
2. Graph
Possible problem:
 Don't see a graph?
Your window has probably not been set properly. See below
for instructions on how to zoom, adjust the window and trace.
Window:
Lets you set the size of the viewing window and adjust the X and Y scales.
Task
How to do it
1. Set the size of the
window.
TI-83 Plus
WINDOW  Enter the Xmin and/or Xmax and/or Ymin
and/or Ymax and/or Xscl and/or Yscl. These determine the
left, right, top and bottom end points of the X and Y axis.
Basnayake
Page 2 of 6
Zoom:
Lets you zoom in on (or out of) any portion of the graph. The various zoom options are as follows:
Task
How to do it
1. To zoom in onto a
particular portion of a
graph
ZOOM  1:ZBox
2. Zoom In
Position the cursor at the top left and corner of the area you
want to zoom in on. Hit ENTER than move the cursor down
and to the right to the bottom left corner of the zoom area and
hit ENTER.
ZOOM  2:Zoom In
3. Zoom Out
Zooms in with the center at the point of the cursor. Default
factor is 4.
ZOOM  3:Zoom Out
4. ZDecimal
Same as above but zooms out.
ZOOM  4:ZDecimal
5. ZSquare
Resets the window to X:[-4.7,4.7] and Y:[-3.1, 3.1]. Trace
key moves in increments of 0.1.
ZOOM  5:ZSquare
6. ZStandard
Adjusts Xmin and Xmax so that the ticks are the same
distance apart on both axes.
ZOOM  6:ZStandard
7. ZTrig
Resets the window to X:[-10,10] and Y:[10, 10]. However,
trace key does not move in increments of 0.1.
ZOOM  7:ZTrig
8.ZInteger
Sets the window to X:[-2π, 2 π] and y:[-4,4].
ZOOM  8:ZInteger
9.ZoomStat
Sets the window to Xscl=10 and Yscl=10
ZOOM  9:ZoomStat
0: ZoomFit
Gives a window that shows all the statistical data points
ZOOM  10:ZoomFit
Sets a window that shows the maximum and minimum value
of Y with the given X window.
TI-83 Plus
Basnayake
Page 3 of 6
Trace
Lets you follow the contour of a graph using the arrow keys. The x- and y- coordinate of the cursor is
displayed on the bottom of the screen.
Task
How to do it
Follow the contour of a
graph
Changing graphs
TRACE  use the left or right arrow keys to move the
cursor along the curve to the left or right.
Use the up (or down) arrow keys to make the cursor jump
from one curve to another.
Note that tracing is easiest if Xscl has been carefully chosen by you.
Finding the intersection of two curves
1.
2.
3.
4.
5.
6.
7.
Press Y= and place the first function in Y1= and the second in Y2=
Press Calc (2nd Trace)
Choose 5:Intersect (#5)
For the First Curve, hit enter.
For the Second Curve, hit enter
For the Guess, arrow to the intersection and press enter (get as close as possible).
The TI-83 will return a value for x and y – the point of intersection.
Finding a Maximum (or minimum)
1.
2.
3.
4.
5.
6.
7.
Press [Y=] and place a function in Y1=
[2nd][TRACE]
Choose 4:Maximum
Move the cursor over to the left side of the maximum and hit [ENTER]
Move the cursor over to the right side of the maximum and hit [ENTER]
Move the cursor over the maximum point and hit [Enter]
The TI-83 will return a value for x and y – the relative maxima.
The procedure for finding a minima is the same except for choosing 3Minimum in set 3.
Absolute Value Functions
1. Press Y=
2. Enter your function next to Y1=. To put absolute value signs, press 2nd and 0 to access the
CATALOG and select abs( from the list. Make sure to close the parenthesis when you are done
entering the portion within the absolute value.
TI-83 Plus
Basnayake
Page 4 of 6
Piecewise Defined functions
 x 2  2 for x  1
Say you want to graph the function f ( x)  
. To enter this we need the inequality
 x+1 for x  1
symbols and they are located in the TEST menu (2nd MATH).
1. Press Y =
2. Enter your function next to Y1 = as follows (note the ( ) are very important!)
Keystrokes
2.1 (X^2 – 2) (X
2.2 2nd MATH
2.3 Choose 5:<
2.4 1 ) + (X + 1) (X
2.5 2nd MATH
2.6 Choose 5:>
2.7 1)
3. GRAPH
Screen
\Y1=(X^ - 2)(X
\Y1=(X^ - 2)(X <
\Y1=(X^ - 2)(X < 1) + (X + 1)(X
\Y1=(X^ - 2)(X < 1) + (X + 1)(X >
\Y1=(X^ - 2)(X < 1) + (X + 1)(X > 1)
Note that your graph may show the two functions as being joined together. This may or may not be
true. Interpret the graph correctly. You may have to calculate the end points by hand.
Finding a solution/zero of an equation graphically
1.
2.
3.
4.
Press [Y=]
Enter your function next to Y1=.
Press [2nd] [Trace]
Choose 2:Zero (#2) and follow the prompts.
Evaluating an equation for a given x- value.
1.
2.
3.
4.
Press [Y=]
Enter your function next to Y1=.
Press [2nd] [Trace]
Choose 1:Value (#1) and follow the prompts
TI-83 Plus
Basnayake
Page 5 of 6
Regression – Fitting a Function to a set of points:
1. Enter a set of points in to L1 and L2 (see Plot points)
2. Press [STAT], choose [CALC], and select one of the functions that fit the data. (Screen shot of
4:LinReg(ax+b))
3. Place L1 and L2 (the x and y values) next to it by typing [2nd] [1], [,] for the comma, and, [2nd][2].
(This tells LinReg, that the x-values are in L1 and that the y-values are in L2. Note the “,” between
L1 and L2 is important!)
4. Place another comma after L2, and type [VAR] Y-VARS  1:Function…1:Y1 to place Y1
on the screen. (This is where the answer is going to go)
5. [ENTER]
Observe the left screen shot has the values of a and b for y = ax+b. Pressing the [Y=] button reveals
the equation entered into the \Y1= position (right screen shot) because we did step 4.
TI-83 Plus
Basnayake
Page 6 of 6