To me a nemonic is supposed to provide an easy way to help you remember something  It shouldnt be hard to remember or hard to remember how to use  The second nemonic I feel is quite complicated has much information buried in it is hard to learn how it all goes together and takes a significant amount of memory to remember how to use all its various parts  Given that is it really a nemonic  A second thing I want to do is give for consideration the nemonic I learned way back when we used paper trig tables  Sorry I do not know a reference for it  And I can not edit it in because I dont know the markup here on Wiki  It is  OH  AH  OhAh  AhOh  HA  HO  Say it moderately fast Sine cosine tangent cotangent secant cosecant are  OH  AH  OhAh  AhOh  HA  HO  Unlike the soacahtoa nemonic it gives all six common functions  But I like to teach only the st three OH AH OhAh simple enough or even only the first two OH AH  and have them students memorize only Sin Cos and Tan   then have them learn and understand that tan sincos and the last three are inverses of the st three  It might sound a bit like a tongue twister at first but it only took a my high school trig class about  minutes to learn it and a good part of that time was laughter  and it is silly enough to be memorable I still use it after  years and some of my todays students have picked it up too as the one they prefer over soh cah toa