arcsin

Inverse Sine Calculator

Calculate arcsin(x) - the inverse sine function for values between -1 and 1

Calculate Inverse Sine

Domain: [-1, 1]

Results

arcsin(0.5) = 30.000000°
Special Angle: 30°

In Degrees

30.000000°

In Radians

0.523599 rad

Explanation

sin(30°) = 1/2, therefore arcsin(1/2) = 30°

Special Values of Inverse Sine

Input (x)arcsin(x) in Degreesarcsin(x) in RadiansExact Value
-1-90°-π/2-π/2 ≈ -1.5708
-√3/2-60°-π/3-π/3 ≈ -1.0472
-√2/2-45°-π/4-π/4 ≈ -0.7854
-1/2-30°-π/6-π/6 ≈ -0.5236
000
1/230°π/6π/6 ≈ 0.5236
√2/245°π/4π/4 ≈ 0.7854
√3/260°π/3π/3 ≈ 1.0472
190°π/2π/2 ≈ 1.5708

Quick Reference

Function
y = arcsin(x)
Inverse sine function
Domain
[-1, 1]
Input must be between -1 and 1
Range
[-π/2, π/2] or [-90°, 90°]
Output is always between -π/2 and π/2
Common Notation
arcsin(x)
sin⁻¹(x)
asin(x)

Properties

Inverse Relationship
sin(arcsin(x)) = x
Odd Function
arcsin(-x) = -arcsin(x)
Pythagorean Identity
arcsin(x) + arccos(x) = π/2
Derivative
d/dx arcsin(x) = 1/√(1-x²)

Understanding the Inverse Sine Function

What is Inverse Sine?

The inverse sine function, denoted as arcsin(x) or sin⁻¹(x), is the inverse function of the sine. It takes a value between -1 and 1 and returns the angle whose sine equals that value.

Key Properties

  • Domain: [-1, 1] - input must be between -1 and 1
  • Range: [-π/2, π/2] radians or [-90°, 90°]
  • The function is increasing (as x increases, arcsin(x) increases)
  • arcsin(x) is an odd function: arcsin(-x) = -arcsin(x)

Applications

The inverse sine function is used in trigonometry, engineering, physics, and computer graphics for finding angles when the sine value is known.

Common Use Cases

  • Finding angles in right triangles
  • Solving trigonometric equations
  • Wave analysis and signal processing
  • Physics calculations involving oscillations

Key Formulas

Basic Definition

y = arcsin(x), where -1 ≤ x ≤ 1
-π/2 ≤ y ≤ π/2 (in radians)
-90° ≤ y ≤ 90° (in degrees)

Relationships

sin(arcsin(x)) = x
arcsin(sin(y)) = y (for -π/2 ≤ y ≤ π/2)
arcsin(-x) = -arcsin(x)
arcsin(x) + arccos(x) = π/2

Step-by-Step Examples

Example 1: Find arcsin(1/2)

Step 1: We need to find the angle whose sine is 1/2

Step 2: From the unit circle, we know sin(30°) = 1/2

Step 3: Since 30° is in the range [-90°, 90°], arcsin(1/2) = 30°

Answer: arcsin(1/2) = 30° = π/6 radians

Example 2: Find arcsin(-√2/2)

Step 1: We need to find the angle whose sine is -√2/2

Step 2: From the unit circle, we know sin(-45°) = -√2/2

Step 3: Since -45° is in the range [-90°, 90°], arcsin(-√2/2) = -45°

Answer: arcsin(-√2/2) = -45° = -π/4 radians