Formulas
This trigonometry ratio uses the fraction adjacent over hypotenuse.
Cosine(x)
1
What is the reference angle of 150º?
30 degrees.
How many radians is equal to 180º?
π radians
In which way do negative angles rotate?
Clockwise
This equation is a way of finding the x-coordinate on a unit circle.
x=cos(theta)
What is sin(150º)?
1/2 or 0.5
What is the reference angle of 45º?
45 degrees
π/2 radians.
Name one fact about the unit circle from its definition.
This trigonometry ratio uses the fraction opposite over hypotenuse.
Sine(theta)
What is cos(3π/2)?
-1/2
60 degrees
How many radians is 135º?
3π/4 radians.
What is (√2/2)2 equal to?
2/4 or 1/2
This trig ratio is what you get when you divide sine by cosine.
tangent
What is sin(4π/3)?
-√3/2
60 degrees (or π/3).
11π/6 radians
What positive angle is coterminal (shares a terminal side with) to -45º?
What is the name of this formula?: cos2x + sin2x = 1
The Pythagorean Identity
What is cos(7π/4)?
-√2/2
What is the reference angle of 5π/4?
45 degrees (or π/4).
How many radians are in 390º?
13π/6 radians.
What negative angle is at the point (-√3/2, -1/2)?
-150º or -7π/6