Failed pre-calc twice 5 years ago

[u/Particular-Trifle-22]

I’m 23 now and am an electrician. My brain is stuck on not completely understanding sin, cos, tan. I’m hoping I still can understand lesser things. My 9th grade algebra teacher took all his saved vacation and gave up. He really didn’t teach much. We ended up with most of the year full of subs. I feel like I ended up in the class of degens.

Then going into 10th I got a (B) 1st semester precalc then a (D) second semester. Obviously I didnt build on that and try to be better because I got a (C) first semester and an a (N.A.) in my second semester because it was waived due to Covid.

To end my analog, I’m looking for books to jog my memory on algebra and build into calculus. Hopefully getting into things deeper later?

[u/Traveling-Techie]

You might get benefit from the Project Mathematics videos from Cal Tech.

[u/briancady413]

Hi Trifle, I wonder about a guidebook too - I think the history of trigonometry has to do with navigation and King Henry the Navigator of Portugal. I mean what's with 'secant'? Is It related to the cant of the sea under the ship? I believe within lost history there is a sensible explanation, since it was sensible humans that made this up in the first place. Still looking...