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Calculates the cosine.
Syntax
double cos( double x );
float cosf( float x );
long double cosl( long double x );
#define cos(X) // Requires C11 or later
float cos( float x );  // C++ only
long double cos( long double x );  // C++ only
Parameters
x
Angle in radians.
Return value
The cosine of x. If x is greater than or equal to 263, or less than or equal to -263, a loss of significance in the result occurs.
| Input | SEH exception | _matherrexception | 
|---|---|---|
| ± QNaN, IND | none | _DOMAIN | 
| ± INF | INVALID | _DOMAIN | 
Remarks
Because C++ allows overloading, you can call overloads of cos that take and return float or long double values. In a C program, unless you're using the <tgmath.h> macro to call this function, cos always takes and returns a double.
If you use the <tgmath.h> cos() macro, the type of the argument determines which version of the function is selected. See Type-generic math for details.
By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.
Requirements
| Routine | Required C header | Required C++ header | 
|---|---|---|
| cos,cosh,cosf | <math.h> | <cmath> or <math.h> | 
| cos() macro | <tgmath.h> | 
For more compatibility information, see Compatibility.
Example
See the example in sin, sinf, sinl.
See also
Math and floating-point support
acos, acosf, acosl
asin, asinf, asinl
atan, atanf, atanl, atan2, atan2f, atan2l
_matherr
sin, sinf, sinl
tan, tanf, tanl