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Example Questions
Example Question #11 : Unit Circle
Suppose there is exists an angle, such that .
For what values of and make this trigonometric ratio possible?
The only values such that
are at the values:
This means that the only choice for is . or achieve the necessary angles to satisfy this trigonometric ratio.
Example Question #11 : Unit Circle
If , and , what is ?
The tangent of an angle yields the ratio of the opposite side to the adjacent side.
If this ratio is , we can see that this is a Pythagorean triple (3-4-5); the absolute value of the sine of this angle would be .
However, the question indicates that this angle lies in the 3rd quadrant. The sine of any angle in the 3rd or 4th quadrant is negative, since it is equivalent to the y-coordinate of the corresponding point on the unit circle.
Therefore,
.
Example Question #11 : Unit Circle And Radians
If , which of the following angles is NOT a possible value for ?
On the unit circle, the cosine of an angle yields the x-coordinate.
There are two angles at which the x-coordinate on the unit circle is : and .
is coterminal with , and is coterminal with .
is in the 4th quadrant, and has a positive x-coordinate.
Example Question #11 : Unit Circle
How many degrees are in a unit circle?
Step 1: Define a Unit Circle:
A unit circle is used in Trigonometry to draw and describe distinct angles. The unit circle works along with the coordinate grid.
Step 2: There are quadrants in the coordinate grid, each quadrant can fit degrees.
Step 3: Multiply how many degrees in quadrant by .. to get the full unit circle:
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