Cosine Calculator
cos(θ) is adjacent/hypotenuse in a right triangle and the x-coordinate on the unit circle.
Cosine is the x-coordinate on the unit circle, or adjacent/hypotenuse in a right triangle.
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Example problems
How this solver works
- Parse cos(angle).
- Use exact values when the angle is a standard position.
Formula
Right-triangle definition.
Worked examples
cos(60°)
- 1/2
Answer: 1/2
Common mistakes
cos(90°) is not 1
cos(90°) = 0. sin(90°) = 1.
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Frequently asked questions
Is cosine even?
Yes. cos(−θ) = cos(θ).