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$asin (aggregation)

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$asin

New in version 4.2.

Returns the inverse sine (arc sine) of a value.

$asin has the following syntax:

{ $asin: <expression> }

$asin takes any valid expression that resolves to a number between -1 and 1, e.g. -1 <= value <= 1.

$asin returns values in radians. Use $radiansToDegrees operator to convert the output value from radians to degrees.

By default $asin returns values as a double. $asin can also return values as a 128-bit decimal as long as the <expression> resolves to a 128-bit decimal value.

For more information on expressions, see Expressions.

Behavior

If the argument resolves to a value of null or refers to a field that is missing, $asin returns null. If the argument resolves to NaN, $asin returns NaN. If the argument resolves to a value outside the bounds of [-1, 1] inclusive, $asin throws an error.

ExampleResults
{ $asin: NaN }NaN
{ $asin: null }null
{ $asin : Infinity}
or
{ $asin : -Infinity } 		Throws an error message resembling the following formatted output: 
"errmsg" :
  "Failed to optimize pipeline :: caused by :: cannot
  apply $asin to -inf, value must in [-1,1]"

Example