Graphing Calculator Programming

 Millions of students use graphing calculators such as the TI-83, TI-84, and TI-89 to assist in the solving of math problems and accelerate tasks. Many schools are very good at teaching students how to use the software that comes preloaded on the graphing calculator, and students often can perform useful tasks after a few months of using one. However, most students do not even know that they can easily program their calculators to maximize their efficiency, expand the functionality of the calculator, and even create games. Although of questionable ethics, students have even used calculator programs to cheat on tests. Due to its simplicity, programming a graphing calculator can also be a very educational experience as an introduction for students to computer programming in general.

One of the most common calculators used by high school students is the TI-84. Programming a TI-84 (or TI-84 Silver Edition) or TI-83 can be done using two languages: TI-Basic and Assembly. TI-Basic is the more simple of the two, and the best for beginners. TI-Basic can be programmed on the computer or directly into the calculator. Programming directly into the calculator is a fantastically simple way to learn, because programs can be tested and corrected almost instantaneously. Below I will show you how to create a sample TI-Basic program that is entered directly into the calculator. Its function will be to solve the quadratic formula given 3 coefficients of a quadratic equation (a, b, c). This is a very useful program for algebra and math analysis classes.

Follow these steps to create a simple quadratic formula program on a TI-83 or TI-84 (This guide is for people who are entirely new to calculator programming):

1. Press the [PRGM] button. (this opens the programming window). The screen you are now seeing shows any programs you've already created or uploaded.
2. Press the Right Arrow twice (on the directional pad in the upper right corner). This takes you to the new program window.
3. Press [Enter]. This creates a new program.
4. Type the name for your program then press [Enter]. It can be whatever you want. I suggest "quadform". To type letters just press [Alpha], then type the key with the green letter above the key.
5. Now it is time to start the actual programming. press the [PRGM] key to bring up the programming commands menu.
6. Press the Right Arrow. This will highlight "I/O" on the top of the screen.
7. Select "Input" and press enter. You can also press 1.
8. After you have entered an input command you need to type "A" (you also need to type the quotes around the A or it will not work). To type a quotation mark press [ALPHA] then [+].
9. Next type a comma [,]. The comma is the key above the [7] key.
10. Type A (just an A, no quotes) Then press [ENTER] to start a new line. Now your first line of code should read: Input "A", A
11. Repeat Steps 5-10 two more times, except replace all A's with B's on the 2nd time and all A's with C's on the third time. When you are done your second line should say: Input "B", B and your third line should say: Input "C", C
12. Next type EXACTLY AS SHOWN: ((-B+√B²-4AC))/(2A))->D then press [ENTER] to start a new line (For clarification, the first "-" symbol is a negative sign. This is found next to the "." key. The symbol after the first "+" is a radical and is accessed by pressing [2ND] then [x²]. The symbol after "B²" is a minus sign and the "->" symbol just before "D" is actually a store command. This is used by pressing the [STO>] key, which is just above the [ON] key. You need to enter in all the parantheses and division signs and stuff exactly as it is written above for this to work.
13. Next type EXACTLY AS SHOWN: ((-B-√B²-4AC))/(2A))->E then press [ENTER](In this line the second "-" is a minus sign. All the other symbols are the same as in step 12)
14. Next press [PRGM] key and then press the RIGHT ARROW. In this menu select the option that says "Disp" and press enter. After Disp type the letter D (without quotes).
15. Press [ENTER] to start a new line and repeat step 14. Instead of typing D type E this time.
16. Your program is now complete (assuming you typed everything correctly, which can be difficult). Press [2ND] then [MODE] to quit your program. You can run the program by pressing [PRGM] then selecting the program you just made. The program will first say A. type the value of the a coefficient in a quadratic equation and press enter. Do the same for B and C. The program will then tell you the two solutions, or zeros for the quadratic equation (Remember, it must be a real quadratic equation to work). If the quadratic equation does not have 3 coefficients, just put zeros in for the ones that are not there.

If you have any questions leave them in the comments box and I will address them. Also, feel free to ask me to write the code for a program idea to tell you how to do it.

Here is another hub (not mine) with helpful programming advice: http://hubpages.com/hub/How-To-Program-a-Graphing-Calculator