Unit circle -- more trig than Excel.

I recall back when I was first learning trig how much more things made sense once I had a solid grasp of the unit circle. When my oldest child was starting to learn trig, I encouraged her to work hard to understand the unit circle when it came up, and the rest of trig would be a lot easier. It was gratifying when she came back and said that it was true. She struggled with trig until she finally grasped the unit circle.

The attached spreadsheet is a relatively simple attempt to illustrate the unit circle and the basic trig functions. There are four nearly identical sheets. In one sheet, you can enter your angles in degrees, in another, you enter you angles in radians, and in the third, you can enter your angles as mulitples of pi radians (since so much of early trig focuses on "simple" angles like pi*1/3 or pi*3/4 or pi*1). The sheets are protected so someone does not "accidentally" enter an angle in the wrong cell on the wrong spreadsheet, but there is no password if you wish to unprotect it. The fourth tab (angles entered in radians) shows some of the other trig functions (tan, cot, etc.) and how they relate to the unit circle (see Wikipedia for more https://en.wikipedia.org/wiki/Unit_circle ).

I think the main interest for this spreadsheet will be those who are learning or re-learning trig and want to try to understand the unit circle.

For those interested in Excel, it might be a good introduction to how one can draw vectors, or see how to use the trig functions in Excel, or other trig related things.