ASIN()
 Computes the sine arc
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 Syntax

     ASIN(<nSine>) --> nSineArc

 Argument

     <nSine>  Designates the angle sine value for which you want the
     response determined in radians.  The value can be in the range of -1 to
     +1 (inclusive).

 Returns

     ASIN() returns the arc sine for <nSine>.

 Description

     ASIN() determines an angle size in radians for a sine value.  The return
     value is in the range of -pi/2 to +pi/2.

 Note

     .  The SETPREC() function can influence the result.

 Example

     Compute the sine arc:

     ? STR(ASIN(0.5), 18, 15)      // 0.523598775598299