β=10(log)_{10}(I/10)^{(-12)}

this one is really cool.you divided the intensity of some sound by 10-12 w/m3 (lowest sound the human ear can recognise) and multiply that by logbase u get to know how loud smth is in bels(times 10 for decibels) -- idk i find that pretty cool.

linear regression is really cool -- like the fact that we can get a formula from the data to then be allowed to make our own "thing" thats the same "type" as the data. idk its really fucking cool m8

complex conjugates in qm -- WARNING ! super watered down.
using the Dirac notation we can write that photons going through horizontaly cut sheet (x with a matrice (1 0)) as |x> and a verticaly cut sheet (y with a matrice (0 1)) as |y>. Now to calculate the probabilty amplitude we need to turn one of ur kets into a bra [making < x|y> (actually |< x|y>|^{2} for the full p amplitude lol)] HOW DO U MAKE A KET INTO A BRA THO? u complex conjugate it :D aka multiply by i ! I find this really cool cause its just another use of imaginary numbers in real life (whatever tf that is) scenarios. p.s. for the interested |< x|y>|^{2} where x=(1 0) and y=(0 1) == 0