As humans, however, degrees ranging from 0 to 360 are much easier to read. That’s why you can and should convert between them with this simple formula.
Radians made no sense to me - until I found out the relationship to PI and then it's a much more natural was of describing angle - especially if you use Tau.
Very classical material, especially if you've ever been (as the author) writing demos/intros in the 80s/90s (http://en.wikipedia.org/wiki/Demoscene). I have many memories of writing basic programs that spat out sine tables, since it wasn't possible to compute something as complex as a sine in real-time.
Yep, and they're still useful: I use a logarithmic computation for fading elements in and out with JavaScript, and by pre-computing the values for each step and storing them in an array, the fade still looks smooth even on older hardware.
I'd love to see this in action - do you have a link? Do you literally serve a precomputed array as part of the JS and iterate over that using opacity/IE filter/whatever, or is it more nuanced than that?
It's not precomputed server-side, it's precomputed when the fade effect is called in the JS. The value for each step is then stored in the task object that performs the fade. Which is cheating a little bit, I suppose, but this way, I can fade from any value to any value, at what appears to be the same "speed", without any glitching.
Reading this tutorial reminded me of the first time I realized how handy a bit of math can be for animation. I think it was this little ease-out snippet that opened my eyes (served me well for years to come):
This is the magic sauce you need. (more visual demo here: http://sol.gfxile.net/interpolation/index.html)