# TI 84 Parametric Equations

TI 84 Parametric Equations are easy to graph. You can even see them in a table. First, you’ll likely have to adjust to thinking in terms of parametric equations. Most of us have been drilled into thinking in terms of rectangular functions. For us, we set y in terms of x. And that’s that.

Now, with parametric equations, a third variable has entered the mix. Once you understand the relationships between the variables, your TI 84 parametric equations will start to make more sense.

## TI 84 Parametric Equations Example 1

Sometimes you learn best by example. So, here’s your example. It’s a basic parametric equation and will show you how to assign expressions to each variable. Basically, both x and y are dependent variables. That means they are in terms of another variable. For parametric equations, x and y are usually in terms of t.

## More Complicated Parametric Equation

For this example, you have both x and y in terms of t-squared. You’re probably used to having y in terms of x-squared. In rectangular coordinates, that’s a parabola.

Now, with both x and y in terms of t-squared, it can still be a parabola. Sometimes it won’t be, sometimes it will be. In this particular example, you still have a parabola. Unlike rectangular coordinates, this graph won’t be a function as it doesn’t pass the vertical line test.

Oh, one last thing: you’ll likely have to keep changing the viewing window. Instead of relying on the default values, you sometimes will have to change the viewing window. I recommend you change the viewing window manually. While it may take a few tries to get it right, it’s worth knowing how to tweak your window until the graph fits.

Good luck!