Proving Trig Identities
This is a video on trig proofs. Here is a timeline.
0:00 - 8:06 - Ground rules for proofs + fundamental identities
8:07 - 13:49 - Example Proof #1
13:50 - 19:06 - Example Proof #2
19:07 - 21:41 - Example Proof #3
21:42 - 24:00 - Example Proof #4
24:01 - 30:20 - Example Proof #5
30:21 - end - Example Proof #6
Of course I could go on with even more examples. Be reminded that it is normal that even after your most careful attention paid to these lessons, you will still find times when you are stuck on these problems. It is considered good advice to use any legal algebra. Your proofs might have different steps from my proofs, but what is important is that your steps are valid, legal algebra, working only one one side of the equal sign, with a careful application of the fundamental identities.