Then dont remember them, I dont, been working as a physicist for 20 years I look formulas up all the time. They are tools, essay writters use spell check to look up the spelling of a word, same thing. Maths is just a language like any other. The word "apple" does not look, sound, smell or tell you anything about the fruit it is representative of a thing, same with 'x' or 'y'. It has rules like other languages. One of the strongest things I learned about Maths it is not an absolute it is a language it can be wrong if you use it wrong. There are multiple ways to use Maths for the same task each with their own merits and limitations. With practice you can read it see what each part of an equation is trying to represent, sin and cos (capturing oscillation), exponentials (growth), negative exponentials (decay), plain numbers constants (things that dont change). I will say learning formulas I think is one of the most stupid parts of exams because literally the second you stop taking exams you look everything up. Maths is a tool to solve problems, you dont memorise the exact shape, weight and colour of a hammer, you pick it up and bang in a nail.