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4.2 The Unit CircleEssential Question:What is the unit circle and what do the points on it represent?

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Special Right Triangles

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Convert to Radians

30o

45o

60o

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The Unit Circle!-Applies x- and y- coordinates to "special angles"

- All angles are multiples of 30, 45, or 60 degrees

- All points are "over 2" and have square root

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Creating the Unit Circle:1) Start in Quad. I and with the y-coordinate of 0.

2) Count to 4 with the y up to 90 degrees or π/2.

3) Count back down on x from 0 to 4.

4) Square root everything, then put over 2.

5) Reflect points to the different Quadrants.

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The 6 Trigonometric FunctionsSo why do we need the unit circle?

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a)

b)

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c)

d)

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Assignment:

4.2 p. 299 #1-51 (odd)

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