MERRY CHRISTMAS

We're going to review some simple stuff today. The first thing we're going to review is reference angles.

Reference angles are really easy and they are needed at various times throughout your entire trigonometry life!

We learned this a few months ago, so you should remember how to do.

Incase you didn't, i'm going to review how to do it. It's very simple

Example 1:

Find the reference angle of Sin 120.

• Because Sin is y/r, you have to find out weather or not y's are negative or positive in the quadrant that 120 is in.
• Because sin 120 is in quadrant II, it is positive.
• Now you have to find the reference angle by making 120 negative and adding 180.
• You now get Sin 60.
• Simplify it completely and you get sqrt3/2

Example 2:

Find the reference angle of Cos 315

• Because Cos is x/r, you have to find out weather or not x's are negative or positive in the quadrant that 315 is in.
• Because Cos 315 is in quadrant 4, it is positive.
• Now you have to find the reference angle by making 315 negative and adding 360.
• You get Cos 45
• Simplify it completely and you get sqrt2/2

Merry Christmas to allllll and to all a good night! :)

Carley :)