the answer to your question is probably a 'soft' yes. by that i mean it likely wouldn't hurt to memorize some formulas, but the way you do it can make a huge difference.
scenario 1: you literally sit there and memorize the mid-point formula and others like it for a few hours, but outside of any meaningful application of the content. you become a flashcard *****.
scenario 2: you do the hundreds of problems contained in destroyer and "memorize" the formulae and how to apply them by virtue of actually using them over and over and over again.
which do you think would better serve you when it comes time to battle the DAT?
there are shortcuts too. for your representative trig functions all you really need to know are your sin and cos values for the first quadrant of a unit circle. the distance formula is just your pythagorean theorem. lots of times, especially in math, if you know one thing you really know several things after some tweaking.
good luck.