Most of students time in Algebra class is spent on analyzing linear and quadratic functions. In the latter half of Algebra 2 and Pre-Calculus, students will do a lot of this analyzing with their graphing calculators. The focus of this article is a function that does get talked about in high school and college math classrooms but just not to degree of the functions (no pun intended) mentioned above.
A quartic function is a polynomial of degree four. This simply means the largest exponent in the problem will be 4. A quartic often looks like two separate quadratic functions pieced together. If you have a set of data that can be modeled by a quartic function, then this means the data will likely rise and fall on more than one occasion.
If you have your data on hand, then you can enter it into your TI-84 (preferred) or TI-83 (acceptable) graphing calculator. You will enter it under the STAT-EDIT menu. On the screen you will have two lists in which you are to enter both your x and y coordinates. X-coordinates will go in list 1, while y-coordinates can be placed in list 2. This is the most important typing step because it can be easy to make a user error here. Everything else the calculator will do on its own, so make sure you double check your data entry.
To actually obtain the quartic equation you will now hit the STAT-CALC buttons on your calculator. You will scroll down towards the bottom until you see something that will described a quartic function. Simply hit ENTER twice and the equation will almost instantaneously flash onto your screen. There are many other things that you can do with this equation with the TI-84, but the process mentioned in this article is crucial for beginners to learn. If you want to actually view the graph, then you need to take the equation you see and enter it into the Y= menu. After inputting in the top row you should be able to hit ZOOM 9 and the graphing window will automatically show the data points you entered into list one and list two earlier.