Sine vs. Cosine: geometry geek-ery
"Circle cos sin" by LucasVB - Own work. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Circle_cos_sin.gif#/media/File:Circle_cos_sin.gif
"Circle cos sin" by LucasVB - Own work. Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Circle_cos_sin.gif#/media/File:Circle_cos_sin.gif