Find the Exact Value cos(-180 degrees )

Problem

cos(−180)

Solution

1. Identify the angle and its position on the unit circle. The angle is −180

2. Apply the property of even functions, which states that cos(−θ)=cos(θ)

3. Rewrite the expression using this property.

cos(−180)=cos(180)

4. Determine the coordinates on the unit circle at 180 The point on the unit circle corresponding to 180 (or π radians) is (−1,0)

5. Recall that the cosine of an angle corresponds to the xcoordinate of the point on the unit circle.

cos(180)=−1

Final Answer

cos(−180)=−1

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