ASin# ( float# )
Parameters
| float - a sine value; must be in the range -1 to 1 |
Description
|
Returns the angle, in degrees, whose sine is the given value. ASin is the inverse of Sin, and it answers in the range -90 to +90 degrees. That is the half of the circle where sine is unambiguous: sine alone cannot tell 30 degrees from 150 degrees, so ASin always picks the one nearest zero. Because of that limit, ASin is best for "how steep is this" questions - the pitch of a slope, how far a ramp climbs over a given distance - rather than for working out a full heading. When you need all 360 degrees, use ATan2 instead, which looks at both components and gets the quadrant right. Values outside -1 to 1 return NaN (not a number), so clamp anything that comes out of a division before you feed it in. See also: Sin, ACos, ATan, ATan2, Pi. |
Example
; ASin Example ; ------------ ; ASin is the inverse of Sin: given a sine value between -1.0 and 1.0, ; it returns the matching angle in DEGREES, from -90 up to +90. Print " value ASin(value)" Print "-----------------------" For n=-4 To 4 v#=n/4.0 Print RSet(v,10)+RSet(ASin(v),12) Next Print "" ; Feeding a sine back through ASin recovers the original angle Print "Sin(30) = "+Sin(30) Print "ASin(Sin(30)) = "+ASin(Sin(30)) Print "" Print "Press any key to close the example" WaitKey End
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