Cosine Calculator

The cosine function (cos) is one of the fundamental trigonometric functions that relates an angle to the ratio of two sides in a right triangle. This calculator computes the cosine of any angle in degrees, providing instant and accurate results for mathematical, scientific, and engineering applications.

Enter any angle in degrees (e.g., 30, 45, 90)

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Mathematical Explanation

The cosine function is defined as cos(θ) = adjacent/hypotenuse in a right triangle. For a unit circle, cosine represents the x-coordinate of a point on the circle at a given angle from the positive x-axis. The cosine function is periodic with period 360° (or 2π radians) and has a range of [-1, 1].

Frequently Asked Questions

The cosine function (cos) is a trigonometric function that calculates the ratio of the adjacent side to the hypotenuse in a right triangle. It's one of the three primary trigonometric functions along with sine and tangent.

cos(0°) = 1. This is one of the commonly memorized trigonometric values from the unit circle.

Cosine (cos) calculates the ratio from an angle, while arccosine (arccos or cos⁻¹) calculates the angle from a ratio. They are inverse functions: arccos(cos(x)) = x.

The cosine function always returns values between -1 and 1, inclusive. No angle will produce a cosine value outside this range.

Cosine and sine are complementary: cos(θ) = sin(90° - θ). Also, cos²(θ) + sin²(θ) = 1 (Pythagorean identity).

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