Applying the cosine ratio of trigonometry, the exact value of cos(-60°) which equals cos (π/3) is: C. 1/2.
What is the Cosine Ratio?
In trigonometry, the vaue of the cosine ratio is the cosine of the reference angle which equals the ratio of the adjcent side over the hypotenuse.
To get the exact value of cos(-60°), convert 60 to radians.
π radian = 180
60° = (π/3) radians
Note: cos (-θ) = cos θ
Therefore, cos (-π/3) = cos (π/3)
cos (π/3) = 1/2
The exact value of cos(-60°) = 1/2 (option C).
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