For a long time I've been looking for a book,or an online course to help me overcome my problems with math.At least on the big from of trigonometry,cause that's what i'll use a lot in game programming.
I know what sin,cos,tan are,how to use them,but in their simplest form.I mean you can ask me to calculate the opposite side with sin,but that's kinda it.
What I mean is that when stuff gets more advanced,I just fail to combine some things to create an equation for example.
I want a book that doesn't spend too much time talking about things,but actually doing stuff.You know,you see a problem solved,then you have to solve one too.And one with answers and explanations would be great,so I know where I'm wrong.
The things that I'm interested in are like: calculating a new trajectory for a ball when it hits a wall.
Regarding your last line in particular, you 'can' use trigonometry for that, but it is a very roundabout way of doing things. Such things use linear algebra instead, specifically simple vector mathematics.
a lot of it just boils down to you calculating the opposite sides honestly so its good that you at least know that. Since this is basic I would recommend any book honestly, what you could do is just get a standard math book, check www.cramster.com where they post solution to problems, go directly to the problem section and try to solve as many as you can and check your results against the solutions they posted on cramster.com ((make sure they have that book before you go buy it!!!)). This will help you understand these functions and their application better as well as develop a good sense of application for these kind of functions.
When it comes down to it you'll have to understand this well yourself and be able to manipulate the equations since there is no one single book that will provide you with all that answer you will ever need with problems that can come up in Game Programming or Life in general. Best of luck to you!
Just to reinforce, luca's answer is the correct one. Most problems in computer graphics can be solved best with linear algebra, particularly the problem you suggested. However, if you are still interested in more advanced trigonometry, I imagine any precalculus text book will have a lot of knowledge on that. Calculus will have some trig stuff too, but it's more about trigonometric functions with respect to differentiation, integration, and differential equations (not sure if that's really what you're looking for).