Find the Exact Value cos((-pi)/4)

Problem

cos(−π/4)

Solution

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

cos(−π/4)=cos(π/4)

2. Identify the reference angle on the unit circle. The angle π/4 radians is equivalent to 45

π/4=45

3. Determine the exact value using the coordinates of the unit circle at π/4 where the xcoordinate represents the cosine value.

cos(π/4)=√(,2)/2

Final Answer

cos(−π/4)=√(,2)/2

Want more problems? Check here!