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Defined in header <math.h> | ||
float cosf(float arg); | (1) | (since C99) |
double cos(double arg); | (2) | |
longdouble cosl(longdouble arg); | (3) | (since C99) |
_Decimal32 cosd32( _Decimal32 arg); | (4) | (since C23) |
_Decimal64 cosd64( _Decimal64 arg); | (5) | (since C23) |
_Decimal128 cosd128( _Decimal128 arg); | (6) | (since C23) |
Defined in header <tgmath.h> | ||
#define cos( arg ) | (7) | (since C99) |
cosl) is called. Otherwise, if the argument has integer type or the typedouble,(2) (cos) is called. Otherwise,(1) (cosf) is called. If the argument is complex, then the macro invokes the corresponding complex function (ccosf,ccos,ccosl).The functions(4-6) are declared if and only if the implementation predefines | (since C23) |
Contents |
| arg | - | floating-point value representing angle in radians |
If no errors occur, the cosine ofarg (cos(arg)) in the range[-1 ; +1], is returned.
The result may have little or no significance if the magnitude ofarg is large. | (until C99) |
If a domain error occurs, an implementation-defined value is returned (NaN where supported).
If a range error occurs due to underflow, the correct result (after rounding) is returned.
Errors are reported as specified inmath_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559):
The case where the argument is infinite is not specified to be a domain error in C, but it is defined as adomain error in POSIX.
#include <errno.h>#include <fenv.h>#include <math.h>#include <stdio.h> #ifndef __GNUC__#pragma STDC FENV_ACCESS ON#endif int main(void){constdouble pi=acos(-1); // typical usageprintf("cos(pi/3) = %f\n", cos(pi/3));printf("cos(pi/2) = %f\n", cos(pi/2));printf("cos(-3*pi/4) = %f\n", cos(-3* pi/4)); // special valuesprintf("cos(+0) = %f\n", cos(0.0));printf("cos(-0) = %f\n", cos(-0.0)); // error handlingfeclearexcept(FE_ALL_EXCEPT);printf("cos(INFINITY) = %f\n", cos(INFINITY));if(fetestexcept(FE_INVALID))puts(" FE_INVALID raised");}
Possible output:
cos(pi/3) = 0.500000cos(pi/2) = 0.000000cos(-3*pi/4) = -0.707107cos(+0) = 1.000000cos(-0) = 1.000000cos(INFINITY) = -nan FE_INVALID raised
(C99)(C99) | computes sine (\({\small\sin{x} }\)sin(x)) (function)[edit] |
(C99)(C99) | computes tangent (\({\small\tan{x} }\)tan(x)) (function)[edit] |
(C99)(C99) | computes arc cosine (\({\small\arccos{x} }\)arccos(x)) (function)[edit] |
(C99)(C99)(C99) | computes the complex cosine (function)[edit] |
C++ documentation forcos | |
