Get down with the lingo
Arc Length
A slice of the circumference. Wear gloves when handling, or you might get cut.
Corresponding Acute Angle
Associated with every angle, there is another angle that is closer to the x-axis.
Coterminal Angles
Angles that occupy the same position on the unit circle.
Even Functions
A function where f(-x) = f(x). No matter how negative x gets, even functions stay positive (relatively speaking).
Negative Angle Identities
sin (-x) = -sin x cos (-x) = cos x Negative angles affect sine and cosine differently.
Odd Functions
A function where f(-x) = -f(x). The function always follows x's lead.
Radian
An alternate measure for angles. 2π radians equals 360 degrees. If someone ever tells you radians are radical, just shake your head sadly and say, "No."
Sector
A portion of a circle. Useful when you can't eat a whole circle, but you're still hungry.
Trigonometric Equation
An equation with trigonometric functions in it. The name kind of says it all.
Unit Circle
A super-handy circle with radius 1. It helps us find the values for trig functions. Be sure to tell it "thank you" for all its help.