EASY math question:No book, have a quiz tonight, need a vector refresh

[pX]

Alright, I am taking a night class in "Statics" and I ordered the very expensive book from half.com for half (how coincidental) the price I'd have to pay at the bookstore. Anyway, there is a quiz tonight, the first. It should be pretty easy, I am just trying to remember a little about resolving vectors. It's really basic stuff at this point, I took electromag last semester so I have did this before, anyway I figure if I can just convert the mag/angle stuff back and forth to cartesian I can do all the probs (prof. has been teaching us to use trig techniques, which seems pointless to me, and I didn't pay attention). OK, I know how to convert from phasor (is that the correct terminology? a mag/angle combination) to cartesian, and I know how to get the magnitude from the cartesian but how do you get the angle? I know it has something to do with inverse tan. For example, what I'm asking is what is lets say 10x-12y in mag/angle form? I know the mag is (244)^(.5) but whats the angle? and what if its 10x-12y+3z ? oh and x,y,z are unit vectors or whatever theyre called....... thanks

 

[Radiohead]

 

[pX]

ok I think it's INVTAN(y/x) where x and y are the components of the vector, someone correct me if I'm wrong here....