 # The Unit Circle Definition of Trigonometric Function

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Examples, solutions, videos, worksheets, games, and activities to help Algebra 2 students learn the unit circle definition of trigonometric function.

The unit circle is a circle with a radius of 1.
In the unit circle, sin θ = y, cos θ = x and tan θ = y/x.

The Unit Circle
Goal:
To see the connection between
1. Sin, Cos, Tan
2. "Special" right triangles
3. The Unit Circle
The Unit Circle
Goal:
Use the unit circle definition of Sin, Cos, Tan to evaluate for theta = 30, 45, 60 degrees.

Trigonometry, Unit Circle
The unit circle plays a key role in understanding how circles and triangles are connected, as well as providing a simple way to introduce the basic trigonometric functions (sine, cosine and tangent). This video describes the unit circle very carefully with the goals of providing basic insights into trigonometry and revealing the motivations behind learning the unit circle. Emphasis is placed on understanding rather than memorization.

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