ForumGeneral Discussion ► Today I Learned <something scientific/historical/academic or just pretty cool>... [Not a Status-update Thread]
The coolest thing about sin2 + cos2 = 1 is less that it's a super important trig identity, it's kinda the trig identity. I'm sure there's some more abstract and arbitrary definition but that's the one I would use to define the functions sin and cos.

That said I'm a dirty physicist and mathematicians always scoff at our proofs and definitions.
  
Yeah, let me tell you, sin2 + cos2 =1 has saved my ass in a couple tests, because it’s the easiest Pythagorean trig thingy to remember AND the basis for the other two Pythagorean things.
  
Everything in math is always so weirdly interconnected. Sometimes I'll be working on a homework assignment and I'll literally mutter to myself "I swear to god, if this turns out to be the Fibonacci sequence or the golden ratio...". And it usually does.
  
A layer of sharpie is about 1 micrometre, a layer of vivid is about 3.
  
If you could fold a piece of paper in half 42 times, it would reach the moon.
  
242 × paper thickness ≥ moon distance? Okay, sure. Except... that's not really "folding" anymore, is it?
  
If you started with a sheet about an AU wide, then I guess it could be.
  
It actually overshoots it by quite a margin, but the paper would need to be enormous and the energy to compress it would be literally astronomical.
  
I remember reading somewhere that you can't fold a piece of paper in half more than 7 times. I'm sure there's some enormous piece of paper out there that can do it, but I've tried it many times and never succeeded.
  
Mythbusters!
  
TIL An internet meme made it into New Zealand politics
  
I've met Chloe Swarbrick, she's a GC
  
In the mediaeval period people thought red hair made you untrustworthy. Chaucer made the Miller red haired to indicate that to his audience.
  
Kylljoy said:

actually, the context was a lot different, and if you watch the video the part where she says "ok boomer" it isn't really directed at the opposing side
  
Grayseff said:
In the mediaeval period people thought red hair made you untrustworthy. Chaucer made the Miller red haired to indicate that to his audience.
I'm pretty sure that stems from a deeper belief that red hair was a sign of selling one's soul to the devil. Or at least that's what I've heard. Supposedly that's where the "gingers have no souls" myth came from.
  
The book I'm reading says nothing about that, purely that it was a sign of being untrustworthy, an excerpt from the mid 1400's even says to avoid staying at an inn if redheads are there.
  
Eh, maybe what I heard was some form of urban myth then.
  
I had thought it was mostly associated with hot temper. To a lesser extent with general villainy and high sex drive.
  
Babe Ruth was an alcoholic.
  
I always love scientific reasoning. For example, what makes some plastic bottles so rigid while some others so pliable? If you want, you can visit my site Fashionneosale. i hope you can get more information.
  
Forum > General Discussion > Today I Learned <something scientific/historical/academic or just pretty cool>... [Not a Status-update Thread]