Wrapping a Line Around a Circle
THE UNIT CIRCLE
The unit circle is a circle, C, of radius 1, centered at the origin (0,0).
As we move up line L, we are going to imagine wrapping the line around C.
The value of t becomes the length of the arc which has been wrapped around C.
Since this is a circle of radius 1
- wrapping around the whole circle () would require a length of .
- wrapping around half the circle () would require a length of .
Investigations of the Wrapping Function
1. Click on the degrees, and click off the Arc Length and Right Triangle.
2. Move the point t up and down the line. Observe the x and y coordinates. 3. Click on right triangle and click off arc length and degrees. 4. Use the right triangle to find the sin(), cos( where is the angle from the positive x axis to the point on the unit circle (not the angle in green. How are the sine and cosine related to the x and y coordinates?Sine of an angle
Which of the following is equivalent to the sin()?
Cosine of an angle
Which of the following is equivalent to the cos()?
Review of Radians
Which of the following is the DEFINITION of the angle measure in radians.
Use the Unit Circle above to find the sin(90)
Use the Unit Circle above to find the radian measure of .
Use the Unit Circle above to find cos()