std:: tan, std:: tanf, std:: tanl
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Defined in header
<cmath>
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| (1) | ||
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float
tan
(
float
num
)
;
double
tan
(
double
num
)
;
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(until C++23) | |
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/* floating-point-type */
tan ( /* floating-point-type */ num ) ; |
(since C++23)
(constexpr since C++26) |
|
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float
tanf
(
float
num
)
;
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(2) |
(since C++11)
(constexpr since C++26) |
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long
double
tanl
(
long
double
num
)
;
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(3) |
(since C++11)
(constexpr since C++26) |
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Additional overloads
(since C++11)
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Defined in header
<cmath>
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||
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template
<
class
Integer
>
double tan ( Integer num ) ; |
(A) | (constexpr since C++26) |
std::tan
for all cv-unqualified floating-point types as the type of the parameter.
(since C++23)
|
A)
Additional overloads are provided for all integer types, which are treated as
double
.
|
(since C++11) |
Parameters
| num | - | floating-point or integer value representing angle in radians |
Return value
If no errors occur, the tangent of num ( tan(num) ) is returned.
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The result may have little or no significance if the magnitude of num is large. |
(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.
The additional overloads are not required to be provided exactly as (A) . They only need to be sufficient to ensure that for their argument num of integer type, std :: tan ( num ) has the same effect as std :: tan ( static_cast < double > ( num ) ) .
Example
#include <cerrno> #include <cfenv> #include <cmath> #include <iostream> // #pragma STDC FENV_ACCESS ON const double pi = std::acos(-1); // or C++20's std::numbers::pi int main() { // typical usage std::cout << "tan(1*pi/4) = " << std::tan(1*pi/4) << '\n' // 45° << "tan(3*pi/4) = " << std::tan(3*pi/4) << '\n' // 135° << "tan(5*pi/4) = " << std::tan(5*pi/4) << '\n' // -135° << "tan(7*pi/4) = " << std::tan(7*pi/4) << '\n'; // -45° // 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(1*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
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(C++11)
(C++11)
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computes sine (
sin(x)
)
(function) |
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(C++11)
(C++11)
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computes cosine (
cos(x)
)
(function) |
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(C++11)
(C++11)
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computes arc tangent (
arctan(x)
)
(function) |
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computes tangent of a complex number (
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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