Trig Question
Find the exact value of Cosine Theta for an angle theta in standard position whose terminal side contains the point (-5,6).

Question

Trig Question
Find the exact value of Cosine Theta for an angle theta in standard position whose terminal side contains the point (-5,6).

mathstudent55 · Answer

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mathstudent55 · Answer

Do you know what a reference angle is?

anonymous · Answer

Ah, So I was suppose to literally use the points -5,6

anonymous · Answer

Sorry no

mathstudent55 · Answer

Yes, you first plot the point you were given.

anonymous · Answer

Would I use the unit circle to determine what my radians are and degrees?

mathstudent55 · Answer

A reference angle is the angle the terminal side of an angle makes with the positive or negative x-axis.

mathstudent55 · Answer

No need for the unit circle.

mathstudent55 · Answer

The trig functions for an angle are the same as they are for its reference angle with only possibly an adjustment in the sign necessary.

mathstudent55 · Answer

Let's start with your problem.
We see in the figure the terminal side.
Now we need to mark the reference angle.

mathstudent55 · Answer

Since the terminal side of your angle is in quadrant 2, the reference angle is the angle the terminal side makes with the NEGATIVE x-axis.

mathstudent55 · Answer

I'm using the Greek letter $\alpha$ (read: alpha) for the reference angle.
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