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Numbers and Their Application - Lesson 16
We already covered in lesson 11 the special
triangles (3-4-5, isosceles right, and 30°-60°-90°).
We also introduced there the basic definitions for
right triangle trigonometry:
We will have to modify/extend these definitions slightly to generalize them
for angles greater than 90° and less than 0°
Some authors refer to these generalized definitions as
circular functions. We will continue to call either trigonometric functions.
The trig functions are part of a general class of functions termed
periodicthey repeat. That is, the dependent variable takes on the
same set of values over and over again.
Reference angle is the smallest non-negative acute or right angle between
the terminal side and either u-axis.