Trigonometry

Radians
When measuring degrees it is often easier and more accurate to do so using radians as a unit.

Definition of a Radian:

If you want to convert an angle measured in degrees to radians, follow this process:

An example using an angle with a measure of 30°:

The process can also be used in reverse:

Standard Position
First, lets look at the rotation of angles.
Positive Rotation: counter-clockwise
Negative Rotation: clockwise

All angles have a terminal side and an initial side:

For an angle to be in standard position it must meet the following criteria:
1. Vertex at the origin
2. Initial side on x-axis

Trigonometric Functions
Remember SOHCAHTOA:

Special Cases
30-60-90 triangles:











45-45-90 triangles:

Unit Circle:
The Unit Circle shows different measurements of angles, and their positions on a graph with a circle centered around the center of a graph and with a radius of 1.

The Unit Circle is based off 30-60-90 and 45-45-90 triangles.

Even and Odd Funtions
All Triganometric funtions are even or odd.

Even Functions:



cosine
secant

Odd Funtions:



sine
tangent
cosecant
cotangent