Calculate the cosine of an angle in degrees or radians with exact values for common angles.
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Result
cos(0°)
Also in Functions
Trigonometry
The cosine calculator computes the cosine of any angle entered in degrees or radians. Exact symbolic values are shown for standard angles.
The cosine of an angle in a right triangle is the ratio of the adjacent side to the hypotenuse. In the unit circle, cos(θ) is the x-coordinate of the point at angle θ.
Cosine values range from -1 to 1 and the function is periodic with period 360° (2pi radians). Cosine is an even function: cos(-θ) = cos(θ).
Common exact values: cos(0°) = 1, cos(30°) = root3/2, cos(45°) = root2/2, cos(60°) = 1/2, cos(90°) = 0. These mirror the sine values shifted by 90°.
Frequently asked questions
1. The cosine of 0 degrees is exactly 1.
sin(θ) = cos(90° - θ). They are co-functions — the sine of an angle equals the cosine of its complement.
Related
These related calculators come from the same leaf category, nearby sibling categories, or the same top-level topic.
Calculate the sine of an angle in degrees or radians with exact values for common angles like 30, 45, and 60 degrees.
Calculate the arccosine (inverse cosine) of a value and return the angle in degrees and radians with exact fractions of pi.
Calculate the arcsine (inverse sine) of a value and return the angle in degrees and radians with exact fractions of pi.
Calculate the arctangent (inverse tangent) of any real number and return the angle in degrees and radians.
