This is a free lesson from our course in Trigonometry
In this lesson you'll learn the relationship of Sine and Cosine to the Unit
Circle. It is explained with the help of examples, video and explanation by instructor
in own hand writing and covers practice questions with solution. A circle with center at the origin and radius 1 is called the unit circle and has the equation
x^{2} + y^{2} = 1. Using the unit circle, you'll gain understanding of some of the properties,
such as domain, range and asymptotes (if any), of the trigonometric functions.
Let
be the measure of central angle and P (x, y) the point on the unit circle.
If the ray from the origin (0, 0) to (x, y) makes an angle
from the positive xaxis, then
sin
= y
cos
= x
Therefore, the coordinates of P are (cos
, sin
).
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