>>12647980If you're "self studying" and you ask questions this vague, I assume you forgot even highschool level math. For this purpose, read Stewart's precalculus. It's to the point and derives formulas in a reasonable way. The thing about math, however, is that you dont memorize shit, at least not for the fundamentals which that book is all about. You must do ALL the exercises in the book. Every new exercise tries to drive you to a common mistake. To really learn the math, after every exercise you must proofcheck your answer working it backwards from result to problem, you must ask yourself What made you make that particular mistake, write down the mistake in a separate notebook, and once it's corrected, ask yourself what can you do to do it faster.
Learn mental math. Abuse multiplication and fractions, abuse the sum of digits. Memorize the addition and substraction of every pair of digits, none of them are trivial. memorize the powers of numbers from 1 to 12 up to the cube, memorize the powers of 2 up to the power of 10.
