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$tanh (aggregation)

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$tanh

New in version 4.2.

Returns the hyperbolic tangent of a value that is measured in radians.

$tanh has the following syntax:

{ $tanh: <expression> }

$tanh takes any valid expression that resolves to a number, measured in radians. If the expression returns a value in degrees, use the $degreesToRadians operator to convert the value to radians.

By default $tanh returns values as a double. $tanh can 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.

ExampleResults
{ $tanh: NaN }NaN
{ $tanh: null }null
{ $tanh: -Infinity }-1
{ $tanh: Infinity }1

Example