Thursday's Definitions

Here's something similar to what we discussed on the board Thursday in Acc. Pre-Calculus.

Vocabulary and Formulas:

An angle is in standard position when the vertex is at the origin and the initial side lies on the
positive side of the x-axis.

The ray that forms the initial side of the angle is rotated around the origin with the resulting ray
being called the terminal side of the angle.

An angle is positive when the location of the terminal side results from a counterclockwise
rotation. An angle is negative when the location of the terminal side results from a clockwise
rotation.

Angles are called coterminal if they are in standard position and share the same terminal side
irregardless of the direction of rotation.

A reference angle is the angle formed between the terminal side of an angle in standard position
and the closest side of the x-axis. All reference angles measure between 0 and 90.

The unit circle is a circle with a radius of 1.

The radian is the length of the arc divided by the radius of the arc for a plane angle subtended by
a circular arc. As the ratio of two lengths, the radian is a "pure number" that needs no unit
symbol. The radian is a unit of angular measure defined such that an angle of one radian
subtended from the center of a unit circle produces an arc with arc length 1.