Arccosine Calculator

The arccosine function (arccos or cos⁻¹) is the inverse of the cosine function. It takes a value between -1 and 1 and returns the angle (in degrees) whose cosine is that value. This calculator provides instant and accurate arccosine calculations for mathematical, scientific, and engineering applications.

Enter a value between -1 and 1

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Mathematical Explanation

Arccosine is the inverse cosine function: if cos(θ) = x, then arccos(x) = θ. The domain is [-1, 1] and the range is [0°, 180°]. Common values: arccos(1) = 0°, arccos(0.5) = 60°, arccos(0) = 90°, arccos(-1) = 180°. The function is also written as cos⁻¹(x) or acos(x).

Frequently Asked Questions

The arccosine function (arccos or cos⁻¹) is the inverse of the cosine function. It takes a value between -1 and 1 and returns the angle whose cosine equals that value. For example, arccos(0.5) = 60° because cos(60°) = 0.5.

arccos(0.5) equals 60 degrees exactly. This is one of the fundamental inverse trigonometric values that appears frequently in mathematics and engineering.

arccos(0) equals 90 degrees, which represents a right angle where the adjacent side is zero.

The arccosine function is only defined for values between -1 and 1 because the cosine function only produces values in this range. Since arccosine is the inverse of cosine, it can only accept values that cosine could have produced.

This calculator returns angles in degrees. If you need the result in radians, multiply the degree value by π/180.

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