$asinh (aggregation)

• $asinh

New in version 4.2.

Returns the inverse hyperbolic sine (hyperbolic arc sine) ofa value.

$asinh has the following syntax:

{ $asinh: <expression> }

$asinh takes any valid expression that resolves to a number.

$asinh returns values in radians. Use$radiansToDegrees operator to convert the output valuefrom radians to degrees.

By default $asinh returns values as a double.$asinh can also return values as a128-bit decimalas long as the <expression> resolves to a 128-bit decimal value.

For more information on expressions, seeExpressions.

Behavior

null, NaN, and +/- Infinity

If the argument resolves to a value of null or refers to a fieldthat is missing, $asinh returns null. If theargument resolves to NaN, $asinh returns NaN.If the argument resolves to negative or positive infinity,$asinh returns negative or positive infinity respectively.

Example

• Inverse Hyperbolic Sine of Value in Degrees
• Inverse Hyperbolic Sine of Value in Radians

The trigonometry collection contains a document thatstores a value along the x axis of a 2-D graph:

{
  "_id" : ObjectId("5c50782193f833234ba90d85"),
  "x-coordinate" : NumberDecimal("1")
}

The following aggregation operation uses the$asinh expression to calculate inverse hyperbolicsine of x-coordinate and add it to the input document usingthe $addFields pipeline stage.

db.trigonometry.aggregate([
  {
    $addFields : {
      "y-coordinate" : {
        $radiansToDegrees : { $asinh : "$x-coordinate" }
      }
    }
  }
])

The $radiansToDegrees expression converts theradian value returned by $asinh to the equivalentvalue in degrees.

The command returns the following output:

{
  "_id" : ObjectId("5c50782193f833234ba90d85"),
  "x-coordinate" : NumberDecimal("1"),
  "y-coordinate" : NumberDecimal("50.49898671052621144221476300417157")
}

Since x-coordinate is stored as a128-bit decimal, the output of$asinh is a 128-bit decimal.

The trigonometry collection contains a document thatstores a value along the x axis of a 2-D graph:

{
  "_id" : ObjectId("5c50782193f833234ba90d85"),
  "x-coordinate" : NumberDecimal("1")
}

The following aggregation operation uses the$asinh expression to calculate inverse hyperbolicsine of x-coordinate and add it to the input document usingthe $addFields pipeline stage.

db.trigonometry.aggregate([
  {
    $addFields : {
      "y-coordinate" : {
        $asinh : "$x-coordinate"
      }
    }
  }
])

The command returns the following output:

{
  "_id" : ObjectId("5c50782193f833234ba90d85"),
  "x-coordinate" : NumberDecimal("1"),
  "y-coordinate" : NumberDecimal("1.818446459232066823483698963560709")
}

Since x-coordinate is stored as a128-bit decimal, the output of$asinh is a 128-bit decimal.