In my experience, the transformations you set up, such as glRotate, glTranslate, and glScale, specify what operations are applied to the ‘primitives’, or shapes that you draw. When you draw a shape, it is sent down the pipeline and you really don’t see or get the results of the calculations until it appears on the screen. OpenGL is not intended to be a calculation library to perform vector operations. There are a few helpful functions, like one that allows you to find out where an onscreen object originated, but they all relate to graphics in some way.
I don’t know why you don’t want to use sin and cos. My best guess
is that you’re not familiar with trigonometry. That is kind of a prerequisite for OpenGL, and it will be difficult to do pretty much anything without knowing the basics there. It isn’t hard to learn though. In my oppinion the only thing scary about Trigonometry is its name. :]