OK, first, I'm a grown man, this is not a homework problem. Well, in a way it is, since I'm teaching myself, but anyway. I have finally graduated to trig and the six basic functions and how they relate. What I'm having a problem with is this: sin/1+cos = 1-cos/sin How is this true? I've done every algebraic manipulation I can think of, but I can't see how this can be. I'll show what I have come up with, using the fact that sin x =y/r and cos x =x/r. It should break down like this: (y/r)/1+(x/r) = [1-(x/r)]/(y/r) Now, here's how I approached it: Left of the equals sign (y/r)/1+(x/r) = y/(r+x) Then right of the equals sign: [1-(x/r)]/(y/r) = (r-x)/y So when does y/(r+x) ever equal (r-x)/y? Thanks for any help provided. And I hope this wasn't too simple for you guys to consider answering.