﻿ Function ASin

# ASin

Calculates the arcsine of a number.

ASin ( expression )

## Parameters

 expression Any value between -1 and 1 (inclusive).

## Return Value

Returns the trigonometric arcsine of the number. Result is in radians.

## Remarks

ASin(x) is mathematically defined only for -1 < x < 1, so ASin() tends to return -1.#IND for other values of x.

## Example

### Example 1

```#include <MsgBoxConstants.au3>

Example()

Func Example()
; Assign a Local variable the arcSine of 0.5.
Local \$fArcSin1 = ASin(0.5)

; Display the result.
MsgBox(\$MB_SYSTEMMODAL, "", \$fArcSin1 & " rad.")

; Assign a Local constant variable the approximate PI number.
Local Const \$PI = 3.141592653589793

; Assign a Local variable the formula to switch from radian to degree (equals to one radian in degree).
Local \$fRadToDeg = 180 / \$PI

; Assign a Local variable a number in degree.
Local \$fArcSin2 = \$fRadToDeg * ASin(1)

; Display the result.
MsgBox(\$MB_SYSTEMMODAL, "", \$fArcSin2 & " deg.")
EndFunc   ;==>Example

```

### Example 2

```; Example of using ASin with degrees
#include <Math.au3>
#include <MsgBoxConstants.au3>

Local \$fDegree = _Degree(ASin(0.5))

MsgBox(\$MB_SYSTEMMODAL, Default, "ASin(0.5) = " & \$fDegree & " degrees")

```