1. 2. The Unit circle

2. The Unit Circle
A circle with radius of 1 Equation x2 + y2 = 1

3. Do you remember 30º, 60º, 90º triangles?
Now they are really! Important

4. Do you remember 30º, 60º, 90º triangles?
Now they are really! Important Even more important Let 2a = 1

5. Do you remember 30º, 60º, 90º triangles?

6. Do you remember 30º, 60º, 90º triangles?

7. Do you remember 45º, 45º, 90º triangles?
When the hypotenuse is 1 The legs are

8. The Unit Circle: Radian Measures and Coordinates

9. How to use the unit circle
We have seen already
cos is the x values of the points
Sin is the y values of the points
There are 4 other trig functions
Tangent (tan) is equal to sin/cos
Cosecant (csc) is the inverse of sin
Secant (sec) is the inverse of cos
Cotangent (cot) is the inverse of tan

10. Examples
sin 60°
cos 270°
sec 90°