1) Radians are a way of measuring angles based on the length of an arc along a circle. To convert radians to degrees, multiply the radian measurement by 180/π. 2) Reference angles are always acute angles formed between the terminal side of a given angle and the x-axis. 3) Coterminal angles are angles that share the same initial and terminal sides and thus represent the same angle position on a unit circle.

1. Mirian Zaruma

2. What to know… Radians Reference angles Coterminal angles Special angles Trig. formulas

6. Special angles These angles have an exact value. Whenever you see them use these values Θ 0⁰ 30⁰ 45⁰ 60⁰ 90⁰ 180⁰ 270⁰ 360⁰ sin Θ 0 1/2 √ 2/2 √ 3/2 1 0 -1 0 cos Θ 1 √ 3/2 √ 2/2 1/2 0 -1 0 1 tan Θ √ 3/3 1 √ 3 undefined 0 undefined 0

7. Trig. Formulas SohCahToa Sin=opposite over hypotenuse Cosine=adjacent over hypotenuse Tangent= opposite over adjacent Tan θ = y = sin θ x cos θ This is your first trig. formula. P(x,y) y x θ 1 Sin θ = y 1 Cos θ = x 1 Tan θ = y x Point P coordinates are (cos θ ,sin θ )

9. See it wasn’t that bad. This is just the basic later on you’ll learn trig. identify other topics of trigonometry.