Give the exact value of each expression. See Example 5.

cos 30°

Question

Give the exact value of each expression. See Example 5.

cos 30°

Accepted Answer

Hello. Today we're going to be determining the exact value of the given trigonometric function. So the function that is given to us is cosine of 60 degrees. Now, in order to figure out the value of this function, we're going to need to use a unit circle. So let's go ahead and draw a unit circle. Now, one thing to note is that for every terminal point on the unit circle, the terminal points are defined as cosine comma S sign. This is where the cosine value represents the X value of every terminal point on the unit circle. So in order to answer cosine of 60 or determine the value of cosine of what we need to do is we need to know the X value of the terminal point at the angle 60 degrees on the unit circle. The angle 60 degrees can be found in the first quadrant of the unit circle. And the terminal point is defined as one divided by two comma square root three divided by two. In this case here, the X value for the terminal point is one divided by two. So what that means is that the value of cosine of 60 degrees is equal to one divided by two. And with that being said, the answer to this problem is going to be a. So I hope this video helps you in understanding how to approach this problem. And I'll go ahead and see you all in the next video.

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Give the exact value of each expression. See Example 5. cos 30°