# How to Make a Quadratic Formula Program on a TI-84 Plus

How to Make a Quadratic Formula Program on a TI-84 Plus
Image Credit: Shanestillz/iStock/GettyImages

Graphic calculators provide an extremely useful function in modern mathematics courses and in a variety of real-world applications. The Texas Instruments series of TI-84 graphing calculators has been a core component of mathematics training for well over a decade. With these calculators, users can not only complete a series of complex mathematical visualizations but also create sophisticated mathematical programs that streamline a variety of otherwise complex mathematical functions.

Creating a quadratic formula calculator program on a TI-84 or TI-84 Plus calculator requires some time and effort, but it rewards the user with a valuable asset that will become a fundamental aspect of their studies for the future.

### Tip

Creating a quadratic formula program on a TI-84 Plus calculator requires a general understanding of the basic input functions of your device. Fortunately, the code for this program can be created relatively easily.

As a first step, it is important to define the formula being used and the specific variables that will be needed to program it successfully. Although it is relatively easy to jump in and begin programming your TI-84 immediately, you will likely spend additional time and effort at a later point revising the work you have done if you don't complete this step.

The quadratic formula that will be used in your program is ax^2+bx+c=0.

There are currently three variables that are integrated into the formula: A, B and C. Each variable will be created within your quadratic formula program and used to reinforce the rest of your efforts. After you have properly identified your quadratic formula program, you can begin moving forward with the actual programming process.

## First Steps in Programming

After powering on your calculator, press the Program button situated next to the Apps and Vars button in the upper rows. Pressing this button takes you to a new menu in which you have the opportunity to create a new program on your calculator. Use the right-arrow key to scroll through the options until you see the New command. Select the Create New option and then input a name for the program.

If this is one of many programs you have created on your calculator or are planning on creating in the future, make sure that you name your program something that is easily identifiable. This will make it easy to access your program at a future date and also help you not make the mistake of accidentally deleting your program when you decide to organize the content on your device.

## Creating the Variables

Now that you have created the name of your program, you can begin initializing the variables that you will use. When the programming screen open, press the right-arrow key and then the 2 key. You should see the word Prompt on your screen, which you can then complete by typing in the variable names, A, B and C.

At this point, you have successfully initialized the necessary variables. When you execute the program, the first thing you will see is a query for the numerical values associated with the variables in question. The next section of programming integrates these variables into the quadratic formula.

## Defining the Formula

After the variables have been created, the next step is to input the formula. Press the Enter key to ensure that you are inputting your program code on a new line. Here, you need to enter the formula in a specific configuration that allows the calculator to take data stored in the A, B and C variables you initialized earlier and then use it within the quadratic formula.

On the next line of programmable code, insert the following formula: (-B+√((B)^2-(4AC)))/(2A))→X.

The nomenclature used here retrieves data stored in variables and uses them as part of the mathematical process. This is not the only line of formulaic code you need, however. Press Enter again and then input the next segment of the formula: (-B+√((B)^2-(4AC)))/(2A))→Y.

Notice how the two distinctive formulas are being used to create a clearly defined X,Y pair. This information is particularly relevant given the applicability of the formula for graphing situations.

## Completing the Quadratic Formula Solver Program

As a final step in the process, you need to display the results of the equation as part of an X, Y pair. To do so, first press Enter to access a new line of programmable code. Then, press the Program button, followed by the right-arrow key, and then the number 3. When executed successfully, this action brings up the Display command on the line of code you are currently working on.

At this point, you have a series of available options depending on how you want the final results presented. As a first step, input a set of open quotes. At this point, any content you type inside the quotes is displayed as part of the final result of the program.

For example, you can type, "The X and Y coordinates are" or something similar. After deciding what you want to input, you then include a closed bracket, followed by ,**x,y**. This last section of code ensures that the X and Y variables are displayed at the end of the content, thus allowing the results of the program to be viewed by the user.