ASIN
ASIN(number) returns the angle in radians, from -pi/2 to pi/2, and #NUM! outside -1 to 1. Worked examples and converting the answer to degrees. Matches Excel.
Syntax
ASIN(number)| Argument | Required | Description |
|---|---|---|
number | Required | A sine value between -1 and 1. |
Examples
Every example below was executed against VisiGrid engine 0.54.0 — not
transcribed from another vendor's documentation. Reproduce any of them with vgrid calc.
| Formula | Result | Notes |
|---|---|---|
=ASIN(1) | 1.57 | π/2 radians, a quarter turn. |
=DEGREES(ASIN(0.5)) | 30.00 | 30 degrees, a hair under after floating-point conversion — hence 30.00 rather than 30. |
=ASIN(2) | #NUM! | No angle has a sine greater than 1. |
The result is in radians
Like every inverse trigonometric function here, ASIN returns radians. Wrap it
in DEGREES for an angle a person will read.
Only half the circle
Two angles in every full turn share each sine — 30 and 150 degrees both have a
sine of 0.5. ASIN returns the one between -90 and 90 degrees. If the other one
is possible in your problem, you need more information than the sine alone.
Inputs just past 1
A value computed to be exactly 1 can come out as 1.0000000000000002 after
floating-point arithmetic, and ASIN of that is #NUM!. When the argument is
the result of a calculation rather than a typed number, clamp it:
=ASIN(MIN(1,MAX(-1,0.5)))Excel compatibility
Matches Excel. Returns radians between -π/2 and π/2.