I started up college about 4 weeks ago, and in one discussion, a fellow student posited a 90° leftward phase shift to convert a cosine function to a sine one. It made sense, but I told him that without proving it, our professor might come up with an exception.

Well, yesterday on the way to the Denver Zoo (mainly)…

Please remember, I was in a car on varying degrees of bumpy roads. 🙂

(Not that I write well on an iPad Pro screen anyway.)

I’ve grown to prefer using radians over degrees (360° = 2π radians). I hated radians in school.

P.S. I really like the program, GoodNotes, on my iPad for handwriting math “show work.”