I saw that the official mocks have questions which require the use of those big formulas. I guessed the answers. I wanted to know if its worth the time to memorise the formulas when there are several others?

They require you to actually calculate them ? In the LOS in the 2013 CFA curriculum only requires to explain and understand the formula, but not calculate. In the 2012 edition, do they mention you need to be able to actually calculate ?