Introduction to the unit circle

1. 4.2 The Unit Circle
Essential Question:
What is the unit circle and what do the points on it
represent?
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2. Special Right Triangles
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3. Convert to Radians
30o
45o
60o
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4. 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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5. 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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7. The 6 Trigonometric Functions
So why do we need the unit circle?
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8. a)
b)
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9. c)
d)
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11. Assignment:
4.2 p. 299 #1-51 (odd)
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