std::tan

Functions

Basic operations

abs(int)labsllabsimaxabs (C++11)
abs(float)fabs
divldivlldivimaxdiv (C++11)
fmod

remainder (C++11)
remquo (C++11)
fma (C++11)
fmax (C++11)
fmin (C++11)
fdim (C++11)
nannanfnanl (C++11)(C++11)(C++11)

Exponential functions

exp
exp2 (C++11)
expm1 (C++11)

log
log10
log1p (C++11)
log2 (C++11)

Power functions

sqrt
cbrt (C++11)

hypot (C++11)
pow

Trigonometric and hyperbolic functions

sin
cos
tan
asin
acos
atan
atan2

sinh
cosh
tanh
asinh (C++11)
acosh (C++11)
atanh (C++11)

Error and gamma functions

erf (C++11)
erfc (C++11)

lgamma (C++11)
tgamma (C++11)

Nearest integer floating point operations

ceil
floor
roundlroundllround (C++11)(C++11)(C++11)

trunc (C++11)
nearbyint (C++11)
rintlrintllrint (C++11)(C++11)(C++11)

Floating point manipulation functions

ldexp
scalbnscalbln (C++11)(C++11)
ilogb (C++11)
logb (C++11)

frexp
modf
nextafternexttoward (C++11)(C++11)
copysign (C++11)

Classification/Comparison

fpclassify (C++11)
isfinite (C++11)
isinf (C++11)
isnan (C++11)
isnormal (C++11)
signbit (C++11)

isgreater (C++11)
isgreaterequal (C++11)
isless (C++11)
islessequal (C++11)
islessgreater (C++11)
isunordered (C++11)

Macro constants

HUGE_VALFHUGE_VALHUGE_VALL (C++11)(C++11)
INFINITY (C++11)
NAN (C++11)
math_errhandlingMATH_ERRNOMATH_ERREXCEPT (C++11)

FP_NORMALFP_SUBNORMALFP_ZEROFP_INFINITEFP_NAN

(C++11)(C++11)(C++11)(C++11)(C++11)

Defined in header `<cmath>`
float tan( float arg );	(1)
double tan( double arg );	(2)
long double tan( long double arg );	(3)
double tan( Integral arg );	(4)	(since C++11)

Computes the tangent of arg (measured in radians).

4) A set of overloads or a function template accepting an argument of any integral type. Equivalent to 2) (the argument is cast to 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 arg 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.

Example

Run this code

#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

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)
Filesystem library (C++17)
Technical Specifications

Common mathematical functions
Special mathematical functions
Floating-point environment (C++11)
Complex numbers
Numeric arrays
Pseudo-random number generation
Compile-time rational arithmetic (C++11)
Numeric algorithms
gcd (C++17)
lcm (C++17)
Generic numeric operations
iota (C++11)
accumulate
inner_product
adjacent_difference
partial_sum