Chapter 8
Circling In on Angles
IN THIS CHAPTER
Discovering alternate trig function definitions
Inserting triangles on the unit circle
Calculating trig functions on the unit circle
In this chapter, you find right triangles drawn on the coordinate plane (x- and y-axes). Moving right triangles onto the coordinate plane introduces many more interesting concepts such as evaluating trig functions and solving trig equations. Also, you become acquainted with a very handy tool known as the unit circle.
The unit circle is extremely important in the real world and in mathematics; for instance, you’re at its mercy whenever you fly in an airplane. Pilots use the unit circle, along with vectors, to fly airplanes in the correct direction and over the correct distance. Imagine the disaster that would result if a pilot tried to land a plane a bit to the left of the runway!
In this chapter, you work on building the unit circle as you review the basics of angles in radians and degrees as they’re found in triangles. With that information, you can place the triangles onto the unit circle (which is also located in the coordinate plane) to solve the problems at the end of this chapter. (You find more ...
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