$acoshReturns the inverse hyperbolic cosine (hyperbolic arc cosine) of a value.
$acoshhas the following syntax:{ $acosh: <expression> }$acoshtakes any valid expression that resolves to a number between1and+Infinity, e.g.1 <= value <= +Infinity.$acoshreturns values in radians. Use$radiansToDegreesoperator to convert the output value from radians to degrees.By default
$acoshreturns values as adouble.$acoshcan 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
null, NaN, and +/- Infinity
If the argument resolves to a value of null or refers to a field that is missing, $acosh returns null. If the argument resolves to NaN, $acosh returns NaN. If the argument resolves to negative infinity, $acosh throws an error. If the argument resolves to Infinity, $acosh returns Infinity. If the argument resolves to a value outside the bounds of [-1, Infinity] inclusive, $acosh throws an error.
Example | Results |
|---|---|
|
|
|
|
|
|
| Throws an error message resembling the following formatted output: |
Example
The trigonometry collection contains a document that stores a value along the x axis of a 2-D graph:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "x-coordinate" : Decimal128("3")}The following aggregation operation uses the $acosh expression to calculate inverse hyperbolic cosine of x-coordinate and add it to the input document using the $addFields pipeline stage.
db.trigonometry.aggregate([ { $addFields : { "y-coordinate" : { $radiansToDegrees : { $acosh : "$x-coordinate" } } } }])The $radiansToDegrees expression converts the radian value returned by $acosh to the equivalent value in degrees.
The command returns the following output:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "x-coordinate" : Decimal128("3"), "y-coordinate" : Decimal128("100.9979734210524228844295260083432")}Since x-coordinate is stored as a 128-bit decimal, the output of $acosh is a 128-bit decimal.
The trigonometry collection contains a document that stores a value along the x axis of a 2-D graph:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "x-coordinate" : Decimal128("3")}The following aggregation operation uses the $acosh expression to calculate inverse hyperbolic cosine of x-coordinate and add it to the input document using the $addFields pipeline stage.
db.trigonometry.aggregate([ { $addFields : { "y-coordinate" : { $acosh : "$x-coordinate" } } }])The command returns the following output:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "x-coordinate" : Decimal128("3"), "y-coordinate" : Decimal128("1.762747174039086050465218649959585")}Since x-coordinate is stored as a 128-bit decimal, the output of $acosh is a 128-bit decimal.