Sine function ...

And another type of function. When something has a pattern that REPEATS, like the giant Ferris wheel we modeled in class, we call it a PERIODIC function. Some of the most well known of these are the trig functions, sine (SIN), cosine (COS), and tangent (TAN). Here's a little review:

 So, that Ferris wheel (the Singapore Flyer) :  We drew a picture to model the situation, and then used cosines to figure out the height off the ground each minute for the 30 minutes it takes to go around the circle once:

 You have to put your calculator in DEGREE mode (push the [MODE] button) before doing this!

 And then, the regression to a SINE function works just the same as to a linear, exponential, or logistic function:

(1) Put the data into L1 and L2 using [STAT] EDIT
(2) Get the regression equation (this time it's [STAT] CALC "C")
(3) Put the equation in using [Y=].
(4) Turn on the StatPlot using [2nd] [Y=] and adjust your [WINDOW]
(5) Graph

Special note: For some reason, even though you put the calculator in DEGREE mode earlier, the SINE regression doesn't use degrees, it uses RADIANS. So to make the graph match up right, switch the mode back to RADIAN.

If you take a look at all the options under [STAT] CALC, you'll see we've only done a few of the very many functions available for calculating regression equations.