To memorize formulas I use NPI (reverse Polish notation) to avoid the use of parenthesis, as this tends to be repeated a lot, but here is the way I use, it can be NPI or Infix expression:
You need a way to memorize the symbols and here is my way of doing it, which I learned from the author M.A. KOHAIN and his book “Mnemotechnics: The Art and Science of Memory Techniques”, well here are some examples:
Use the name of the equation as the peg for the equation to memorize, it can be using substitute word or you can break the name into single letters and create places for example A - airplane, E - ear, C - carpet, etc…, this is relatively simple and you can store the equations in the letters that define it, remember that after having everything you must make it unique, for example in one the plane falls in flames, an ear with an eye inside, etc., well here everything is left to your inner criterion of how that image would be, remember it is an image what you create with movement, seeing it in 3d is very strong, in 2d too, so play with it.
Symbol - Images, actions or affections.
Addition - Acts of creativity or improvement.
Subtraction - Acts of destruction or disfigurement.
Multiplication - Substances of creation.
Division - Substances of destruction.
Derivative - Quality of creation.
Integral - Quality of destruction.
Exponent - Acts from above.
Root - Acts from below.
Parenthesis - Substances of containment or delimiting images.
Equality - Juxtaposed images that do not interact causally.
Delta - Triangular forms.
Decimal - Acts of emergence.
Consecutivity - Some Elongated Connection.
For Latin letters that often appear in mathematical formulas:
Adapted - Numerical value - Character.
Α α - alpha - 1 - Alan Ritchson.
Β β - beta - 2 - Ben Hardy
Γ ɣ - gamma - 3 - Gabriel Howell
Δ δ - delta - 4 - Dexter (Michael C. Hall)
Ε ε - epsilon - 5 - Ephraim Sykes
Ζ ζ - dseta - 7 - Dzidra Ritenberga
Η η - eta - 8 - Etan Cohen
Θ θ - zeta - 9 - Zeta Makrypoulia
Ι ι - iota - 10 - Ione Skye
Κ κ - kappa (tb. cappa) - 20 - Kayla Wallace
Λ λ - lambda - 30 - Lacey Chabert
Μ μ - mi - 40 - Michelle Randolph
Ν ν - ni - 50 - Nico Parker
Ξ ξ - xi - 60 - Xi Qi
Ο ο - omicron - 70 - Omiros Poulakis
Π π - pi - 80 - Pip Torrens
Ρ ρ - ro - 100 - Rosa Salazar
Σ σ ς - sigma - 200 - Stephanie Sigman
Τ τ - tau - 300 - Tau Wan Yue
Υ υ - ípsilon - 400 - Ipsita Paul
Φ φ - fi - 500 - Fiona Gubelmann
Χ χ - ji - 600 - Jill Wagner
Ψ ψ - psi - 700 - Phillipa Soo
Ω ω - omega - 800 - Omar Epps
Now remember that there are several letters that usually appear in the formulas, but we won’t worry about this, just put any character, shape or thing that comes to mind that begins with this or that letter or preferably create a predefined list of character, action and object in the manner of giordano bruno, you will only need to use the following categories to make the images different from each other for example substance, quantity, quality, place, time, state/condition, action and affection…, so that apart from changing one of these from the previous form or substance you can make something new and distinctive.
My last advice is to practice solving mathematical problems using AI, that is, solve exercises and ask for the results and analyze where you make the mistake and keep a record of the areas in which you falter and usually make mistakes, but when you solve a doubt, write it down so you can review it, which rules you usually ignore when solving equations, so you will have a deep knowledge of the subject, memorizing concepts is relatively simple since you can use characters and make them reflect the concept since there can be several events from one character, also memorizing equations is not complex at all based on my experience.