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Thursday, April 17, 2014

BQ #2 Unit T

How do the trig graphs relate to the unit circle?
The trig graphs relate to the unit circle with the use of the quadrants in the unit circle.For example sine is positive in quadrants 1 and 2 so the graph will be positive through pi since the end of the second quadrant is 180. As soon as the graph passes pi it becomes negative because that's where in quadrant 3 sine becomes negative. The graph will stay negative through quadrant 4, 2pi, because of the unit circle. Once the graph gets to 2 pi the graph as well as the unit circle start over. Since the pattern of this will begin again, the first whole time the graph goes through the unit circle is called a period. This is how the graph of a trig function comes from the unit circle.

Why is period for sine and cosine 2pi whereas period for tangent and contingent is pi?
This is so because sine and cosine have to go through the whole unit circle before it repeats itself again and to go around the whole unit circle is 360 degrees, or 2pi. Tangent and cotangent is only pi because in the unit circle their quadrants are positive negative positive negative. So within the first two quadrants tangent has gone through a period because after that it will already start repeating itself. The end of quadrant 2 would be 180 or pi. Leaving tangent and cotangent pi to become a period.

 How does the fact that sine and cosine have amplitudes of one (and the other trig functions don’t have amplitudes) relate to what we know about the Unit Circle?
Sine and cosine are the only trig functions that have amplitudes because these are the only ones that have restrictions. In the unit circle sine and cosine can't be greater than 1 our less than -1. All the other trig functions do not have restrictions therefore they do not contain amplitudes.

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