$tanhNew in version 4.2.
Returns the hyperbolic tangent of a value that is measured in radians.
$tanhhas the following syntax:{ $tanh: <expression> } $tanhtakes any valid expression that resolves to a number, measured in radians. If the expression returns a value in degrees, use the$degreesToRadiansoperator to convert the value to radians.By default
$tanhreturns values as adouble.$tanhcan also return values as a 128-bit decimal if the<expression>resolves to a 128-bit decimal value.For more information on expressions, see Expressions.
Behavior
null, NaN, and +/- Infinity
If the input argument resolves to a value of null or refers to a
field that is missing, $tanh returns null. If the
argument resolves to NaN, $tanh returns NaN. If
the argument resolves to negative or positive Infinity,
$tanh returns -1 or 1 respectively.
Example | Results |
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Example
The following trigonometry collection contains a document
that stores an angle value measured in degrees:
db.trigonometry.insertOne( { "_id" : ObjectId( "5c50782193f833234ba90d45" ), "angle" : NumberDecimal( "53.1301023541559787031443874490659" ) } )
The following aggregation operation uses the
$tanh expression to calculate the hyperbolic
tangent of angle and adds it to the input document using
the $addFields pipeline stage:
db.trigonometry.aggregate( [ { $addFields : { "tanh_output" : { $tanh : { $degreesToRadians : "$angle" } } } } ] )
The $degreesToRadians expression converts the
angle in degrees to radians.
Example output:
{ "_id" : ObjectId("5c50782193f833234ba90d45"), "angle" : NumberDecimal("53.1301023541559787031443874490659"), "tanh_output" : NumberDecimal("0.7293303448445332820512777329448416") }
Because angle is stored as a 128-bit decimal, the $tanh output is also a
128-bit decimal.
The following trigonometry collection contains a document
that stores an angle value measured in radians:
db.trigonometry.insertOne( { "_id" : ObjectId( "5c50782193f833234ba90d55" ), "angle" : NumberDecimal( "1.6301023541559787031443874490659" ) } )
The following aggregation operation uses the
$tanh expression to calculate the hyperbolic
tangent of angle and adds it to the input document using
the $addFields pipeline stage:
db.trigonometry.aggregate( [ { $addFields : { "tanh_output" : { $tanh : "$angle" } } } ] )
Example output:
{ "_id" : ObjectId("5c50782193f833234ba90d55"), "angle" : NumberDecimal("1.6301023541559787031443874490659"), "tanh_output" : NumberDecimal("0.9260761562750713360156803177935379") }
Because angle is stored as a 128-bit decimal, the $tanh output is also
a 128-bit decimal.