This video is in the chapter about taking limits of sine and cosine as well, but I put it here because so many students as me about it that I want to make it as easy as possible to find!
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...)