std::tan, std::tanf, std::tanl
Defined in header <cmath> |
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(1) | ||
float tan ( float arg ); |
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float tanf( float arg ); |
(since C++11) | |
double tan ( double arg ); |
(2) | |
(3) | ||
long double tan ( long double arg ); |
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long double tanl( long double arg ); |
(since C++11) | |
double tan ( IntegralType arg ); |
(4) | (since C++11) |
arg
(measured in radians).
double
).
Parameters
arg | - | value representing angle in radians, of a floating-point or Integral type |
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 |
(until C++11) |
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 (to which C++ defers), 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 <iostream> #include <cmath> #include <cerrno> #include <cfenv> #pragma STDC FENV_ACCESS ON const double pi = std::acos(-1); int main() { // typical usage std::cout << "tan (pi/4) = " << std::tan( pi/4) << '\n' // 45 deg. << "tan(3*pi/4) = " << std::tan(3*pi/4) << '\n' // 135 deg << "tan(5*pi/4) = " << std::tan(5*pi/4) << '\n' // -135 deg << "tan(7*pi/4) = " << std::tan(7*pi/4) << '\n'; // -45 deg // special values std::cout << "tan(+0) = " << std::tan(0.0) << '\n' << "tan(-0) = " << std::tan(-0.0) << '\n'; // error handling std::feclearexcept(FE_ALL_EXCEPT); std::cout << "tan(INFINITY) = " << std::tan(INFINITY) << '\n'; if (std::fetestexcept(FE_INVALID)) std::cout << " FE_INVALID raised\n"; }
Possible output:
tan (pi/4) = 1 tan(3*pi/4) = -1 tan(5*pi/4) = 1 tan(7*pi/4) = -1 tan(+0) = 0 tan(-0) = -0 tan(INFINITY) = -nan FE_INVALID raised
See also
(C++11)(C++11)
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computes sine (\({\small\sin{x} }\)sin(x)) (function) |
(C++11)(C++11)
|
computes cosine (\({\small\cos{x} }\)cos(x)) (function) |
(C++11)(C++11)
|
computes arc tangent (\({\small\arctan{x} }\)arctan(x)) (function) |
computes tangent of a complex number (\({\small\tan{z} }\)tan(z)) (function template) |
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applies the function std::tan to each element of valarray (function template) |
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C documentation for tan |
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