
I also "wing it" a bit, working example problems I've never done before, so that you can see that even Trig Masters don't always see exactly how to solve a proof when they first see it, and that often it comes down to "messing around with it" and trying a few things before you find the path that will get you to the solution. Trig Cheat Sheet Definition of the Trig Functions 2 Right triangle definition For this definition we assume that 0 2 << or 0 90°< < °. If you need reminded of what these are, you might want to download my Trig Cheat Sheet as most of the important facts and formulas from a trig class are listed there. Most notably are the half-angle and double-angle formulas. The reality is that trig proofs are tough, even for teachers, and the only reason the teacher can make it look so easy is they've been teaching the same problems year after year! That's why in the videos below I break trig proofs down for you, revealing the Big Three basic types of trig proof that almost every proof falls into, and showing you the step-by-step process for working each type out. There are many important trig formulas that you will use occasionally in a calculus class.

Trig Proofs & Identities: 3 Tricks to Make Them Easier The biggest problem with trig proofs (other than the word "proof" causing flashbacks to geometry) is that teachers tend to make them look way too easy in class, so students get discouraged when they can't just whip them off the top of their heads like Teacher.
