The Unit Circle

Move the point around the unit circle. Notice the points E=(cos(θ), sin(θ)) and B. This should help you see that in relation to the unit circle, the cos(θ) is equal to the x value,
and the sin(θ) is equal to the y value.

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Questions to think about:
1. As you move the point around the circle, what do you notice about the points E, and B.

2. What are some of the reasons that you can think of that make this true.

3. How can knowing this help you determine the sin(θ) and the cos(θ)? What are the sin(45°) and the cos(45°) equal to?

Jennifer Ord, Created with GeoGebra