This is my very first post - so i hope I don't break any rules - its more of a formula rearranging question/confirmation so here goes... 1. The problem statement, all variables and given/known data Currently working on friction - static/kinetic - so in my text book it states in a side bar "info bit" that tanθ=sinθ/cosθ my question is : can this equation be rearranged - see below... 2. Relevant equations so if tanθ=sinθ/cosθ then does sinθ=(tanθ)(cosθ) and does cosθ=sinθ/tanθ 3. The attempt at a solution I haven't come across any questions so far where i would need to use sinθ=(tanθ)(cosθ) and cosθ=sinθ/tanθ - more or less a general question of would I encounter having to use the sinθ=(tanθ)(cosθ) and cosθ=sinθ/tanθ rather than tanθ=sinθ/cosθ - numerically it works, but are these variations used? Hope this wasn't clear as mud... If i can provide any more info - let me know!