Probably tangential... I learned what sin() and cos() did experimentally.
There was a BASIC program in Creative Computing that used sin() to make a long snake of text scroll down the screen. So, in my mind, sin() and cos() were things that made wavy lines.
A little while later I was puzzling over how to draw a circle. I had this epiphany that the X component was drawing a wave, just like sin(), and the Y component was drawing a wave that was just out of phase. I went home and programmed it and it worked instantly.
We had a Britannica at home, so I finally looked up what sin() and cos() were, and the diagrams made it all obvious.
It's good that we now have Wikipedia and all, but kids today are still deprived of a computer that comes with a decent programming environment, that makes fun stuff like graphics dead simple.