arctan

Inverse Tangent Calculator

Calculate arctan(x) - the inverse tangent function for any real number

Calculate Inverse Tangent

Domain: All real numbers (-∞, ∞)

Results

arctan(1) = 45.000000°
Special Angle: 45°

In Degrees

45.000000°

In Radians

0.785398 rad

Explanation

tan(45°) = 1, therefore arctan(1) = 45°

Special Values of Inverse Tangent

Input (x)arctan(x) in Degreesarctan(x) in RadiansExact Value
-√3-60°-π/3-π/3 ≈ -1.0472
-1-45°-π/4-π/4 ≈ -0.7854
-1/√3-30°-π/6-π/6 ≈ -0.5236
000
1/√330°π/6π/6 ≈ 0.5236
145°π/4π/4 ≈ 0.7854
√360°π/3π/3 ≈ 1.0472

Quick Reference

Function
y = arctan(x)
Inverse tangent function
Domain
(-∞, ∞)
All real numbers
Range
(-π/2, π/2) or (-90°, 90°)
Output is always between -π/2 and π/2
Common Notation
arctan(x)
tan⁻¹(x)
atan(x)

Properties

Inverse Relationship
tan(arctan(x)) = x
Odd Function
arctan(-x) = -arctan(x)
Asymptotes
lim x→±∞ arctan(x) = ±π/2
Derivative
d/dx arctan(x) = 1/(1+x²)

Understanding the Inverse Tangent Function

What is Inverse Tangent?

The inverse tangent function, denoted as arctan(x) or tan⁻¹(x), is the inverse function of the tangent. It takes any real number as input and returns the angle whose tangent equals that value.

Key Properties

  • Domain: All real numbers (-∞, ∞)
  • Range: (-π/2, π/2) radians or (-90°, 90°)
  • The function is increasing (as x increases, arctan(x) increases)
  • arctan(x) is an odd function: arctan(-x) = -arctan(x)
  • Has horizontal asymptotes at y = ±π/2

Applications

The inverse tangent function is widely used in mathematics, engineering, physics, computer graphics, and machine learning for angle calculations and activation functions.

Common Use Cases

  • Finding angles in coordinate geometry
  • Solving trigonometric equations
  • Navigation and GPS calculations
  • Computer graphics and 3D rotations
  • Machine learning activation functions

Key Formulas

Basic Definition

y = arctan(x), where x ∈ (-∞, ∞)
-π/2 < y < π/2 (in radians)
-90° < y < 90° (in degrees)

Relationships

tan(arctan(x)) = x
arctan(tan(y)) = y (for -π/2 < y < π/2)
arctan(-x) = -arctan(x)
arctan(x) + arctan(1/x) = π/2 (for x > 0)

Step-by-Step Examples

Example 1: Find arctan(1)

Step 1: We need to find the angle whose tangent is 1

Step 2: From the unit circle, we know tan(45°) = 1

Step 3: Since 45° is in the range (-90°, 90°), arctan(1) = 45°

Answer: arctan(1) = 45° = π/4 radians

Example 2: Find arctan(√3)

Step 1: We need to find the angle whose tangent is √3

Step 2: From the unit circle, we know tan(60°) = √3

Step 3: Since 60° is in the range (-90°, 90°), arctan(√3) = 60°

Answer: arctan(√3) = 60° = π/3 radians

Example 3: Find arctan(0)

Step 1: We need to find the angle whose tangent is 0

Step 2: From the unit circle, we know tan(0°) = 0

Step 3: Since 0° is in the range (-90°, 90°), arctan(0) = 0°

Answer: arctan(0) = 0° = 0 radians