Stop spamming the forum unless you have something actually useful to contribute. Anyone can look up articles and we have all learned this stuff way back in high school anyway.
Get a grip - its NOT spam, and you started it. Did you learn somethning yet?
If’n you had a ‘brain’ in your head (you apparently don’t) you would know that calculus and the sciences use the natural radian unit ALMOST exclusively in formulas and calculations ... used to drive me crazy -
what is 60 Hz in Radians? 376.991 Radians/sec.