This video will introduce sum and difference formulas - an awesome way to find even MORE exact values of trig functions using what we know about the unit circle :)
Source: Created by Crystal Kirch using Camtasia for Mac
This is the same idea as part 1, but this time we will use the DIFFERENCE formulas instead of the SUM formulas.
Source: Created by Crystal Kirch using Camtasia for Mac
Part 3 is quick and easy - I'm going to give you the "answer" (not simplified) and you must recognize what sum and difference formula is being used.
Source: Created by Crystal Kirch using Camtasia for Mac