## Introduction: How to Create Programs on a Graphing Calculator

(Specifically Intended for **TI-83** or **TI-84 Plus** Users)

Ever wish that you could have a program on your calculator to do long drawn out formulas for you? With this tutorial you will be able to program formulas into your calculator with ease.

This is for anyone who wants an easier human-error proof way to derive the answer to several formulas. It is especially handy for those among us who are engineers and don’t want to do computation by hand.

You can program any formula that uses inputs into your calculator using this process. You can program formulas such as the formulas for Reynold’s Number, the Quadratic Formula, Antoine’s Equation, the volume of a sphere, Pythagorean Theorem; the possibilities are endless. For demonstration purposes I will be using the coding for the quadratic formula.

**At the bottom of the instructions I have an *"If you messed up really badly"* section that should be noted here just in case you find yourself in a dark abyss with your program and don't know where else to turn.** **What You Will Need**

-A TI-83 or TI-84 plus calculator (these instructions may work for other calculators as well)

-A copy of your specific formula

-A previously calculated answer for your formula so that you can test out your program to see if it is working correctly

## Step 1: Familiarize Yourself With Specific Keys

I have outlined several keys that you will be using during this process. I have only highlighted the ones that I feel are used most frequently in this tutorial those that are harder to find. I think it is safe to assume that most are calculator savvy and know where to find keys such as “**ENTER**” and “**CLEAR**”.

## Step 2: Give Your New Program a Name

Push the **PRGM** (program) button.

Using the right arrow key, scroll over to the tab that says “**NEW**”.

Press **ENTER**.

Type in the name you want your program to be ( Since the calculator automatically locked the keys on alpha you don’t have to push **ALPHA** every time you want to add another character but you will have to later on) .

I am making my program name my initials: **SEK**

## Step 3: Find the Menu I/O

Press **ENTER** after you are done inputting your formula’s name.

Press **PRGM** .

Using the right arrow key scroll over to **I/O**.

## Step 4: Type in the Variables for Your Formula

Select **prompt** by pressing **2** on your ten key pad.

Type in the variables that you will include in your formula. You will have to press **ALPHA** every time for each new character. Separate the variable with a **comma** (button right above the 7) and once you are done press **ENTER**.

## Step 5: Type in Your Actual Formula

Now it’s time to type in your formula. Remember to include your variables by pressing alpha beforehand. If you mess up, don’t worry just scroll over the letter and press **DEL** (delete which is 2 buttons right of the 2nd button).

Once you are done typing the formula, press **STO->** (1 button above the ON button). This will allow you to set your formula equal to a value such as X. After that press **ENTER**.

If you have more than one line of information for your formula, simply press **ENTER**, which will start the next line of code beginning with a colon **(:).** You can store the second value as another variable such as Y as seen below for the quadratic formula.

## Step 6: Find Disp Under I/O Menu

Press **PRGM**, scroll over to** I/O** and select** Disp** (display) by pressing **3** on the 10 key pad. **Disp** is how you want your answer to be displayed.

## Step 7: Tell Your Calculator What Your Outputs Are

If you have just *one* output you can write whatever variable you assigned your formula to equal immediately after **Disp**.

If you have *2 outputs* press **ALPHA** then **(+)** to input quotations. Press **ALPHA** then **zero** on the ten key pad for a space. Do this 12 times. Your cursor should land right under the “**s**” in Disp on the line above.

## Step 8: Tell Your Calculator How You Want Your Function Displayed

Press **ALPHA** then X or whatever variable you want your function to be assigned to.

## Step 9: Find the Equals Sign

Type in an **equal sign** by pressing the **2nd** button and then the** MATH **button (2 buttons below the 2nd button. Select **1** which is **=**.

After the equals sign type in “,X,Y (for those with 2 outputs in their formula)

## Step 10: Test Your Program Out

Now you have finished the programming, but **DO NOT PUSH CLEAR**. Push **2nd MODE** to get out of the screen you are on.

To use the program push **PRGM** and select the program you will want to use.

Press **ENTER** after you see your program’s name and the prompts will follow for what you want to input your values as. Press **ENTER **after each input and after your final input press **ENTER** and your answer should be displayed to the right of the screen.

This is the time to make sure that your calculated value is conclusive with the value that you had previously obtained by other means.

If you followed my example of the quadratic equation your ending result should look like what I have on the screen above.

## Step 11: If You Messed Up Really Bad...

If you messed up you can always press **PRGM**, scroll over to** EDIT** and fix your errors.

If you messed up so badly that you want to delete your program push **2nd MEM (+)**

Select **Mem Mgmt/Del…** by pressing** 2**

Select ** Prgm... ** by scrolling down or pressing **7**.

Scroll down to the program you want to delete and press **DEL**.

You Will be prompted with a message asking **“Are You Sure?”** and if you are sure select **YES** by either scrolling and pressing **ENTER** or pressing **2**.

Press **2nd MODE** and you will exit that screen.

## Step 12: Tips and Other Resources

Remember if you navigate to a screen that you don’t want by accident you can usually get back by pressing **CLEAR.**

Press the **DEL** key anytime you want to delete a single character. If you press **CLEAR** that will delete the entire line.

If you find yourself completely lost always remember to press **2nd MODE** which is essentially “quit” for calculators. That will take you back to the main screen where calculations are done.

OTHER RESOURCES

http://www.ticalc.org/programming/columns/83plus-bas/cherny/

http://www.wikihow.com/Create-Programs-on-a-Ti-83-Graphing-Calculator

https://www.instructables.com/id/TI-83-or-84-into-to-program-creating/step2/begin-the-program/

So, as I said just a moment ago, this was a VERY helpful Instructable.

This will be a great help for working through repetitive problems.

Thanks again.

Your results are incorrect because the order of the numbers in the final step of testing the program is actually 1,3,2 not 1,2,3 (as in, A=1 B=3 and C=2). I had the same problem before I realized that I had read it wrong!

I'm getting some involved notation and imaginary numbers with following your example exactly. I'm guessing its in settings, but fumbling for a few moments has not paid off so far. Any suggestions?

Also, this is a great Instructable with strong enough descriptions in each step it was enjoyable following along.

Thank you.

How do you get the equal sign after the X under Disp?

press 2nd, MATH and then ENTER