This video involves a couple of annoyingly specific formulas for sine and cosine. On the down side, they'll have you asking "why would anyone ever want to know this?" On the other hand, if you see a sine or cosine in a limit problem, chances are this video will cover them!
The Squeeze Theorem
These problems have a funny name, but they're pretty tricky to master. The key thing to let you know you might have one of these on your hands is if you're taking a limit of sine or cosine and two things are true: 1) there's an X in front of the sine or cosine, and 2) there's an X in the denominator of the "argument" of the trig function, like sin(1/x) or cos(pi/x).
If you do not have an account, you should get one, because it is awesome! You can save a playlist for each test or each chapter, and save your "greatest hits" into a "watch right before the final" list (not that we recommend cramming, but when in Rome...)