An In-depth Look at the Unit Circle (Part 3)

Summary/Quick review. This is what we have learned so far. It’s important that you know where these values came from! That’s why we taught you how we got to these values before giving you this chart! It would be very helpful to memorize this chart!

The first quadrant can reflect onto all the other  three quadrants. 

     Notice that in the first quadrant, all the values are positive. In the second quadrant, the cosine values are negative. In the third quadrant, both the cosine and sine values are negative, and in the fourth quadrant, the sine values are negative.