Usually learning the equations teach you the relationships between variables. If you can memorize all of the equations you need and be able to write it down on a paper in 10 minutes then it definitely would be nice to just have to look at a memorized "cheat sheet" instead of have to dig around your brain for it. Basically do whatever you feel is best for you, but it definitely doesn't hurt, and can only help incase you start to become fatigued during the exam you can just look at your sheet.