$tan (aggregation)
$tan
Returns the tangent of a value that is measured in radians.
$tan
has the following syntax:{ $tan: <expression> } $tan
takes any valid expression that resolves to a number. If the expression returns a value in degrees, use the$degreesToRadians
operator to convert the result to radians.By default
$tan
returns values as adouble
.$tan
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
null
, NaN
, and +/- Infinity
If the argument resolves to a value of null
or refers to a field
that is missing, $tan
returns null
. If the
argument resolves to NaN
, $tan
returns NaN
.
If the argument resolves to negative or positive infinity,
$tan
throws an error.
Example | Results | |||
---|---|---|---|---|
{ $tan: NaN } | NaN | |||
{ $tan: null } | null | |||
or
| Throws an error message resembling the following formatted output:
|
Example
The trigonometry
collection contains a document that
stores one side and one angle in a right-angle triangle:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "angle_a" : NumberDecimal("53.13010235415597870314438744090659"), "side_a" : NumberDecimal("3") }
The following aggregation operation uses the
$tan
expression to calculate the side opposite
to angle_a
and add it to the input document using the
$addFields
pipeline stage.
db.trigonometry.aggregate([ { $addFields : { "side_b" : { $multiply : [ { $tan : {$degreesToRadians : "$angle_a"} }, "$side_a" ] } } } ])
The $degreesToRadians
expression converts the
degree value of angle_a
to the equivalent value in radians.
The command returns the following output:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "angle_a" : NumberDecimal("53.13010235415597870314438744090659"), "side_a" : NumberDecimal("3") "side_b" : NumberDecimal(4.000000000000000000000000000000000") }
Since angle_a
and side_a
are stored as
128-bit decimals, the output of
$tan
is a 128-bit decimal.
The trigonometry
collection contains a document that
stores the hypotenuse and one angle in a right-angle triangle:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "angle_a" : NumberDecimal("0.9272952180016122324285124629224288"), "side_a" : NumberDecimal("3") }
The following aggregation operation uses the
$tan
expression to calculate the side adjacent
to angle_a
and add it to the input document using the
$addFields
pipeline stage.
db.trigonometry.aggregate([ { $addFields : { "side_b" : { $multiply : [ { $tan : "$angle_a" }, "$side_a" ] } } } ])
The command returns the following output:
{ "_id" : ObjectId("5c50782193f833234ba90d85"), "angle_a" : NumberDecimal("0.9272952180016122324285124629224288"), "side_a" : NumberDecimal("3") "side_b" : NumberDecimal("3.999999999999999999999999999999999") }
Since angle_a
and side_a
are stored as
128-bit decimals, the output of
$tan
is a 128-bit decimal.