tan, tanf, tanl
| Defined in header <math.h>
|
||
| float tanf( float arg ); |
(1) | (since 哋它亢99) |
| double tan( double arg ); |
(2) | |
| long double tanl( long double arg ); |
(3) | (since 哋它亢99) |
| _Decimal32 tand32( _Decimal32 arg ); |
(4) | (since 哋它亢23) |
| _Decimal64 tand64( _Decimal64 arg ); |
(5) | (since 哋它亢23) |
| _Decimal128 tand128( _Decimal128 arg ); |
(6) | (since 哋它亢23) |
| Defined in header <tgmath.h>
|
||
| #define tan( arg ) |
(7) | (since 哋它亢99) |
tanl) is called. Otherwise, if the argument has integer type or the type double, (2) (tan) is called. Otherwise, (1) (tanf) is called. If the argument is complex, then the macro invokes the corresponding complex function (ctanf, ctan, ctanl).|
The functions (4-6) are declared if and only if the implementation predefines |
(since 哋它亢23) |
Parameters
| arg | - | floating-point value representing angle in radians |
Return value
If no errors occur, the tangent of arg (tan(arg)) is returned.
|
The result may have little or no significance if the magnitude of arg is large. |
(until 哋它亢99) |
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.
Error handling
Errors are reported as specified in math_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559):
- if the argument is ±0, it is returned unmodified;
- if the argument is ±∞, NaN is returned and FE_INVALID is raised;
- if the argument is NaN, NaN is returned.
Notes
The case where the argument is infinite is not specified to be a domain error in C, but it is defined as a domain error in POSIX.
The function has mathematical poles at π(1/2 + n); however no common floating-point representation is able to represent π/2 exactly, thus there is no value of the argument for which a pole error occurs.
Example
#include <errno.h> #include <fenv.h> #include <math.h> #include <stdio.h> #ifndef __GNUC__ #pragma STDC FENV_ACCESS ON #endif int main(void) { const double pi = acos(-1); // typical usage printf("tan(pi*1/4) = %+f\n", tan(pi * 1 / 4)); // 45 deg printf("tan(pi*3/4) = %+f\n", tan(pi * 3 / 4)); // 135 deg printf("tan(pi*5/4) = %+f\n", tan(pi * 5 / 4)); // -135 deg printf("tan(pi*7/4) = %+f\n", tan(pi * 7 / 4)); // -45 deg // special values printf("tan(+0) = %f\n", tan(0.0)); printf("tan(-0) = %f\n", tan(-0.0)); // error handling feclearexcept(FE_ALL_EXCEPT); printf("tan(INFINITY) = %f\n", tan(INFINITY)); if (fetestexcept(FE_INVALID)) puts(" FE_INVALID raised"); }
Possible output:
tan(pi*1/4) = +1.000000
tan(pi*3/4) = -1.000000
tan(pi*5/4) = +1.000000
tan(pi*7/4) = -1.000000
tan(+0) = 0.000000
tan(-0) = -0.000000
tan(INFINITY) = -nan
FE_INVALID raisedReferences
- 哋它亢23 standard (ISO/IEC 9899:2023):
- 7.12.4.7 The tan functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.1.7 The tan functions (p: TBD)
- 哋它亢17 standard (ISO/IEC 9899:2018):
- 7.12.4.7 The tan functions (p: 175)
- 7.25 Type-generic math <tgmath.h> (p: 272-273)
- F.10.1.7 The tan functions (p: 378)
- 哋它亢11 standard (ISO/IEC 9899:2011):
- 7.12.4.7 The tan functions (p: 240)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- F.10.1.7 The tan functions (p: 519)
- 哋它亢99 standard (ISO/IEC 9899:1999):
- 7.12.4.7 The tan functions (p: 220)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- F.9.1.7 The tan functions (p: 457)
- 哋它亢89/C90 standard (ISO/IEC 9899:1990):
- 4.5.2.7 The tan function
See also
| (哋它亢99)(哋它亢99) |
computes sine (sin(x)) (function) |
| (哋它亢99)(哋它亢99) |
computes cosine (cos(x)) (function) |
| (哋它亢99)(哋它亢99) |
computes arc tangent (arctan(x)) (function) |
| (哋它亢99)(哋它亢99)(哋它亢99) |
computes the complex tangent (function) |