What is the domain of arccos?

The domain of arccos is [-1, 1]. You can only input values between -1 and 1 (inclusive). Values outside this range will result in an error.

What is the range of arccos?

The range of arccos is [0°, 180°] (or [0, π] radians). This is the principal value range that makes arccos a function.

📐 Arccos Calculator (Inverse Cosine)

Calculate arccos(x) with full precision and domain validation.

Arccos Calculator

Value(Domain: -1 ≤ x ≤ 1)

arccos(x) =

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Arccos, also written as cos⁻¹, is the inverse function of cosine. Given a value between -1 and 1, arccos returns the angle (in radians or degrees) whose cosine equals that value. The range of arccos is 0° to 180° (or 0 to π radians).

Quick Examples

Common arccos values you might encounter.

arccos(1) = 0° or 0 rad

The angle whose cosine is 1 is 0 degrees.

arccos(0.5) = 60° or π/3 rad

The angle whose cosine is 0.5 is 60 degrees.

arccos(0) = 90° or π/2 rad

The angle whose cosine is 0 is 90 degrees.

arccos(-1) = 180° or π rad

The angle whose cosine is -1 is 180 degrees.

Use Cases

Common applications of the arccos function.

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Triangle Solving

Finding angles from side ratios
Solving inverse trigonometric problems
Calculating unknown angles

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Education

Understanding inverse functions
Learning trigonometric identities
Calculus applications

Frequently Asked Questions

Common questions about the arccos function.

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Last updated: 2025-10-21 — Compiled and reviewed by Calvin (Math Research, FreeCalculators.app)