Find the Exact Value cos(180)

Problem

cos(180)

Solution

1. Identify the position of the angle 180 on the unit circle.

2. Determine the coordinates (x,y) at 180 which corresponds to the point (−1,0)

3. Apply the definition of the cosine function on the unit circle, where cos(θ)=x

4. Substitute the xcoordinate from the point (−1,0) to find the value.

Final Answer

cos(180)=−1

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