>The sine, cosine, and tangent functions are still just black boxes to me, I have no idea what they actually do
They are functions which tell you how to relate different parameters of a triangle. Concepts in mathematics are often interconnected, and trig functions appear in a lot of other (interesting) contexts as well, but fundamentally I don't see them as anything "more" than the SOHCAHTOA you were taught at school.
> or how I would calculate their values.
Without a lookup table? You would need some kind of a way to express the functions in terms of other mathematical functions which you know how to do, like multiplications and additions. Sometimes you can do this with a series expansion. Computers sometimes use a variant of the CORDIC algorithm. Both of those things are clever ideas in their own right, but you don't need to understand them to know what trig functions do.
> I often daydreamed about finding myself on a desert island, needing to make use of trigonometry to rebuild civilization, but not being able to find the angles that I needed.
If you had a circle, a ruler, a pen and some paper then you'd get the idea to make yourself a lookup table pretty quickly!
I think the point I'm making is that we get used to assuming that knowledge is so deep and complex a thing that we can never really know anything. But often, knowledge isn't as intricate as that. If everyone forgot about trig functions today, they'd be rediscovered tomorrow.
The thing is YAGNI applies here. "What if society collapses?" is really just a LARP justification for doing whatever you already wanted to do.
It's why "preppers" buy an armory of weapons, but don't make friends with their neighbors, become contributors to their local town or advocate for infrastructure improvements or sustainable farming policies.
> It's why "preppers" buy an armory of weapons, but don't make friends with their neighbors
Interestingly, when I've seen interviews with deeply committed preppers, they almost always seem to come around to the conclusion that community is the most significant factor in their planning.
I find it fascinating how that juxtaposes with the (possibly well earned) cliche of preppers as intensely individualist libertarians who reject society. I suspect there's some relationship here to the idea that if you go far enough to the left or right, you find that the spectrum is circular and not linear.