Number.Asin
NumberReturns the arcsine (inverse sine) of a number, in radians.
Syntax
Number.Asin(number as nullable number) as nullable numberParameters
| Name | Type | Required | Description |
|---|---|---|---|
number | number | Yes | A value in the range [-1, 1] whose arcsine is computed. |
Return Value
number — The arcsine of the number in radians, in the range [-π/2, π/2].
Remarks
Number.Asin is the inverse of Number.Sin. Given a sine value in [-1, 1], it returns the angle in radians whose sine equals that value. The result is in the range [-π/2, π/2] (−90 to 90 degrees). All trigonometric functions in Power Query M work in radians, not degrees.
Input values outside [-1, 1] return NaN rather than raising an error. Validate inputs when working with computed values that might drift slightly outside [-1, 1] due to floating-point arithmetic — for example, clamp inputs using Number.Max(-1, Number.Min(1, value)) before calling Number.Asin.
To convert the radian result to degrees, multiply by 180 / Number.PI. Number.Asin is the principal value (restricted to [-π/2, π/2]), which means it only unambiguously recovers angles in the first and fourth quadrants. For angles in all four quadrants, use Number.Atan2.
Examples
Example 2: Convert result to degrees — arcsine of 0.5 is 30 degrees
Number.Asin(0.5) * 180 / Number.PIResult | |
|---|---|
| 1 | 30 |