NAME¶

std::tanh,std::tanhf,std::tanhl - std::tanh,std::tanhf,std::tanhl

Synopsis¶

Defined in header <cmath>
float tanh ( float arg );
float tanhf( float arg ); (since C++11)
double tanh ( double arg ); (1) (2)
long double tanh ( long double arg );
long double tanhl( long double arg ); (3) (since C++11)
double tanh ( IntegralType arg ); (4) (since C++11)

1-3) Computes the hyperbolic tangent of arg
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 of a floating-point or Integral type

Return value¶

If no errors occur, the hyperbolic tangent of arg (tanh(arg), or

earg
-e-arg
earg
+e-arg

) is returned.

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, ±0 is returned
* If the argument is ±∞, ±1 is returned
* if the argument is NaN, NaN is returned

Notes¶

POSIX specifies that in case of underflow, arg is returned unmodified, and if that
is not supported, and implementation-defined value no greater than DBL_MIN, FLT_MIN,
and LDBL_MIN is returned.

Examples¶

// Run this code

#include <iostream>
#include <cmath>

int main()
{
std::cout << std::showpos
<< "tanh(+1) = " << std::tanh(+1) << '\n'
<< "tanh(-1) = " << std::tanh(-1) << '\n'
<< "tanh(0.1)*sinh(0.2)-cosh(0.2) = "
<< std::tanh(0.1) * std::sinh(0.2) - std::cosh(0.2) << '\n'
// special values:
<< "tanh(+0) = " << std::tanh(+0.0) << '\n'
<< "tanh(-0) = " << std::tanh(-0.0) << '\n';
}

Output:¶

tanh(+1) = +0.761594
tanh(-1) = -0.761594
tanh(0.1)*sinh(0.2)-cosh(0.2) = -1
tanh(+0) = +0
tanh(-0) = -0

See also¶

sinh
sinhf computes hyperbolic sine (\({\small\sinh{x} }\)sinh(x))
sinhl (function)
(C++11)
(C++11)
cosh
coshf computes hyperbolic cosine (\({\small\cosh{x} }\)cosh(x))
coshl (function)
(C++11)
(C++11)
atanh
atanhf computes the inverse hyperbolic tangent
atanhl (\({\small\operatorname{artanh}{x} }\)artanh(x))
(C++11) (function)
(C++11)
(C++11)
computes hyperbolic tangent of a complex number
tanh(std::complex) (\({\small\tanh{z} }\)tanh(z))
(function template)
tanh(std::valarray) applies the function std::tanh to each element of valarray
(function template)