Calculus

Haven't used it yet outside of academia, but then again I'm an office admin. Was there a specific question, or did you want to know when you would use it?

No

lol, this stream is so dead tho

Lmao yes

Trig

If you're asking how it works outside of academia, that just might be applicable in careers that utilize higher math (such as engineering). You will probably have the formulas at your fingertips in the form of calculators, computers, or internet browsers.