TI-83 Tutorial for Business Calculus

GETTING TO THE HOME SCREEN

- The home screen is the screen where all calculations are performed. To get to the home screen press

ADJUSTING THE CONTRAST

- To
**darken**the screen, press and then hold down the . If you look in the upper right corner of the screen you should see numbers increasing. If the number appearing is a 7 or 8 and your screen is still light, your batteries need to be replaced. - To
**lighten**the screen, press and hold down the . If you look in the upper right corner of the screen you should see numbers decreasing.

SETTING THE WINDOW

- Press to obtain the following menu.
Changes can be made by putting the cursor next to the item you want changed, type in the
new values, and then press .
The value for x-min must be smaller than the value of x-max. The same
is true for y-min and y-max.

- To obtain a standard window (the window setting shown above) press
and selecting
. The dimensions of this viewing window are [x-min,x-max]X[y-min,y-max]=[-10,10]X[-10,10].*6:ZSandard*

CLEARING PROGRAMS

- For the TI-83
- Press .
- Choose
.**2:Delete** - Choose
.**7:Prgm** - Put the cursor next to the program you want to delete and press . You should see the program deleted from the list of programs. Repeat this step if more programs need to be deleted.

- For the TI-83 Plus
- Press .
- Choose
.**2:Mem Mgmt/Del** - Choose
**7:Prgm** - Use and put the cursor next to the program you want to delete. To delete the program press . The question "Are you sure?" is displayed on the screen. To delete the program
choose
. The calculator will return you to the program screen and the program should be deleted. Repeat this process for each program you wish to delete.**2:yes**

CREATING A SCATTERPLOT

- Clear all data from lists by pressing and choosing
*4:ClrList*. This will take you back to the home screen. - Now press
.
Your screen should like the following.
If it does then press and the calculator should respond with

**Done**. - Press then select
*1:Edit...* - Input the
*x*values into*L*and the_{1}*y*values into*L*._{2} - Press to
access the scatterplot
menu. Select
Make the screen look like the folllowing*1:Plot 1...* - Press and adjust your window so all data points can be seen on the screen.

GRAPHING A FUNCTION

- Press . If a previous function is displayed, put the cursor on the function and press .
- Enter the function. To enter a function like
*f (x) = x*, press the following keys.^{4}- 2x^{2}+ 1 - Press to display the graph. You may need to adjust your window to see the graph. A good window to use for this example is [-4,4]X[-10,10].

FINDING THE MAXIMUM

- Press and input the function.
- Press and choose
.*4:maximum*

- At the bottom of the screen the words "Left Bound?" appear. Use the or to move the cursor to the left of the maximum (peak) and press , should appear at the top of the screen marking the left bound.
- At the bottom of the screen the words "Right Bound?" appear. Use the to move the cursor to the right of the maximum (peak) and press . The top of the screen should now have . These two arrows must be facing each other.
- At the bottom of the screen the word "Guess?" appears. Use the to move the cursor close to the maximum and press . The maximum point is displayed at the bottom of the screen.

FINDING THE MINIMUM

- Press and input the function.
- Press and choose
.*3:minimum*

- At the bottom of the screen the words "Left Bound?" appear. Use the or to move the cursor to the left of the minimum (valley) and press , should appear at the top of the screen marking the left bound.
- At the bottom of the screen the words "Right Bound?" appear. Use the to move the cursor to the right of the minimum (valley) and press . The top of the screen should now have . These two arrows must be facing each other.
- At the bottom of the screen the word "Guess?" appears. Use the to move the cursor close to the minimum and press . The minimum point is displayed at the bottom of the screen.

GRAPHING A PIECEWISE FUNCTION

- Press and move the cursor so it is blinking on "Dot".
Press to highlight "Dot".

- To graph

press . Next to*Y*= enter the first piece of the function by pressing._{1}choose

continue by pressing*5: <* The inputting of the first piece of the function is now complete. Repeat this process to enter the other two pieces of the function. When the entire piecewise function is typed into the calculator the screen should look like the one below. Notice the x-intervals are always place between parentheses. Pay particular attention to the way the x-interval for the second piece of the function was inputted. - Press . Your screen should like the graph below.
You may need to adjust your window to see the graph.

FINDING X-INTERCEPTS (a.k.a ZEROS or ROOTS)

- Press and enter the function.
- Press .You may need to adjust your window to see the graph.
- Press to access the calculate menu.
- Choose
.*2:zero*

- At the bottom of the screen the words "Left Bound?" appear. Use the or to move the cursor to the left of the point where the graph crosses the x-axis and press , should appear at the top of the screen marking the left bound.
- At the bottom of the screen the words "Right Bound?" appear. Use the to move the cursor to the right of the point where the graph crosses the x-axis and press . The top of the screen should now have . These two arrows must be facing each other.
- At the bottom of the screen the word "Guess?" appears. Use the
to move the cursor close to the point where the graph crosses the x-axis and press
. The
*x*-intercept (a.k.a. root or zero), is displayed at the bottom of the screen.

FINDING INTERSECTIONS

- Press and enter the functions.
- Press .You may need to adjust your window to see the graph.
- Press to access the calculate menu.
- Choose
.*5:intersect*

- At the bottom of the screen the words "First Curve?" appear. At the top of the screen the equation of the function that the blinking cursor is on is displayed. If the blinking cursor is not on one of the two graphs you want to find the intersection of, press and the blinking cursor will jump to another graph. When the blinking cursor is on one of the two graphs you want to find the intersection of, press .
- At the bottom of the screen the words "Second Curve?" appear. At the top of the screen the equation of the function that the blinking cursor is on is diplayed. If the blinking cursor is not on the graph of the second function you are calculating the intersection of, press and the blinking cursor will jump to another graph. When the blinking cursor is on the second of the two graphs you want to find the intersectin of, press .
- At the bottom of the screen the word "Guess?" appears. Use the or to move the cursor close to the point of interesection and press . The point of intersection is displayed at the bottom of the screen.

CONSTRUCTING A TABLE

- Press and enter a function.
- Press and a table is displayed. To scroll up or down the table put the cursor in the "X" column and press or .
- To change the increments of the
*x*values go to Setting up the table .

SETTING UP THE TABLE

- Press . The following screen is displayed.
- It is recommended that auto is highlighted for both the independent and dependent variable.
- Press to display the table.

Regression (finding a best fitting model)

- Activating the R
^{2}- Press to access the catalog.
- Arrow down to DiagnosticOn and press . This will take you to the home screen.
- Press and the calculator will respond with done.

- Press and clear all functions.
- Follow the instructions for creating scatterplots to display the data.
- Press and to access the CALC menu. Select the number that corresponds with the type of regression needed.
Once you have chosen the type of regression needed, your calculator will automatically go to the home screen. - Press and to
*Y-VARS*. - Select
. Then select**1:Function**and press . The regression information, along with the R**1:Y1**^{2}value, will appear on the screen. - Press and the regression equation appears in Y1.
- Press to see the data points and regression model displayed. You may need to adjust your window to see the graph.
- To find other regression models for the same data, go back to step 5 and repeat the process.

Using the TVM Solver

- If you have a TI-83 press , then select
. If you have a TI_83 plus, press , select**1:TVM Solver**, then*1:Finance*. The TVM solver screen and the definitions of each variable are shown below.*1:TVM Solver* - After the appropriate information has been inputed into the calculator, put the cursor on the variable you are solving for and press . The answer will appear in the location of the cursor.

Finding the Derivative at a Point

- Graphically
- Press and enter the function.
- Press .You may need to adjust your window to see the graph.
- Press to access the calculate menu.
- Choose
.*6:dy/dx* - Input the
*x*value to be evaluated and press . The derivative for the specified*x*value will appear at the bottom of the screen.

- Computationally
- Press and choose
.*8: nDeriv(* - Enter the function you are taking the derivative of.
- Press .
- Enter the value at which you want to evaluate the derivative and press . The answer is displayed on the home screen.

- Press and choose

Draw a Tangent Line

- Press and enter the function.
- Press .You may need to adjust your window to see the graph.
- From the graph screen, press to access the draw menu.
- Choose
*5:Tangent(* - Input the
*x*value where the tangent line is to be drawn and press . The tangent line will be drawn and the equation of the tangent line is displayed at the bottom of the screen.

Evaluating a Definite Integral

- Graphically
- Press and enter the function you want to integrate.
- Press .You may need to adjust your window to see the graph.
- Press to access the calculate menu.
- Choose .
- At the bottom of the screen the words "Lower Limit?" appear. Enter the lower limit of integration and press .
- At the bottom of the screen the words "Upper Limit?" appear. Enter the uppper limit of integration and press .
- The area under the curve is drawn and the answer to the definite integral is displayed at the bottom of the screen.

- Computationally
- Press and choose
.*9: fnInt(* - Enter the function you want to integrate.
- Press
- Enter the lower limit of integration.
- Press .
- Enter the upper limit of integration.
- Press . The answer to the definite integral is displayed on the screen.

- Press and choose