Evaluate cos(-45 degrees )

Problem

cos(−45)

Solution

1. Apply the even-odd identity for the cosine function, which states that cos(−θ)=cos(θ)

cos(−45)=cos(45)

2. Identify the value of cos(45) using the unit circle or a special right triangle (45−45−90.

cos(45)=√(,2)/2

Final Answer

cos(−45)=√(,2)/2

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