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Unit Circle Formula
Demonstration of the Unit Circle Formula & Graph
The Unit Circle is a circle with a radius of 1. The angle that we rotate the radius uses the greek letter θ.
Formula for the Unit Circle
The formula for the unit circle relates the coordinates of any point (x,y) on the unit circle to sine and cosine. According to the formula, the x coordinate of a point on the unit circle is cos(Θ) and the y coordinate of a point on the unit cricle is sin(Θ) where Θ represents the measure of an angle that goes counter clockwise from the positive x-axis. This formula is much easier to see and understand from a picture. See the first problem below.
Picture of the unit circle.
The first lesson to learn
about the unit circle is what should repalce the red questions marks below. In other words, what is the x and the y coordinates of any point on the unit circle.
The value of the x coordinate is the cos(Θ) and the y coordinate is sin(Θ).
Identifying Cosine, Sine and Tanent lines in the Unit Circle
The circle below has a radius of 1.
Which line segment represent
Remember the formula for the unit circle. Cosine represents the x value, segment AB, sine reprsents the y value or CB and the tangent line rests outside the circle and is DF
The circle below has a radius of 1.
Which line segment represent
Remember the formula for the unit circle. Cosine represents the x value, segment AB, sine reprsents the y value or CB and the tangent line rests outside the circle and is DF
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