$cos (aggregation)¶
Definition¶
$cos
¶New in version 4.2.
Returns the cosine of a value that is measured in radians.
$cos
has the following syntax:{ $cos: <expression> } $cos
takes any valid expression that resolves to a number. If the expression returns a value in degrees, use the$degreesToRadians
operator to convert the result to radians.By default
$cos
returns values as adouble
.$cos
can also return values as a 128bit decimal as long as the<expression>
resolves to a 128bit 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, $cos
returns null
. If the
argument resolves to NaN
, $cos
returns NaN
.
If the argument resolves to negative or positive infinity,
$cos
throws an error.
Example  Results  

{ $cos: NaN }  NaN  
{ $cos: null }  null  
or
 Throws an error message resembling the following formatted output:
