Asinh
Defined in header <cmath>
.
Description
Computes the inverse hyperbolic sine of num
.
The library provides overloads of std::asinh for all cv-unqualified floating-point types as the type of the parameter num
(od C++23).
Additional Overloads are provided for all integer types, which are treated as double.
Declarations
- C++23
- C++11
// 1)
/* floating-point-type */ asinh( /* floating-point-type */ num );
// 2)
float asinhf( float num );
// 3)
long double asinhl( long double num );
// 4)
template< class Integer >
double asinh ( Integer num );
//1 )
float asinh ( float num );
// 2)
double asinh ( double num );
// 3)
long double asinh ( long double num );
// 4)
float asinhf( float num );
// 5)
long double asinhl( long double num );
// 6)
template< class Integer >
double asinh ( Integer num );
Parameters
num
- floating-point or integer value
Return value
If no errors occur, the inverse hyperbolic sine of num
(sinh-1(num), or arsinh(num)) 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
or ±∞
, it is returned unmodified
if the argument is NaN, NaN is returned
Notes
Although the C standard (to which C++ refers for this function) names this function "arc hyperbolic sine", the inverse functions of the hyperbolic functions are the area functions. Their argument is the area of a hyperbolic sector, not an arc. The correct name is "inverse hyperbolic sine" (used by POSIX) or "area hyperbolic sine".
The additional overloads are not required to be provided exactly as Additional Overloads.
They only need to be sufficient to ensure that for their argument num of integer type,
std::asinh(num)
has the same effect as std::asinh(static_cast<double>(num))
.
Examples
#include <cmath>
#include <iostream>
int main()
{
std::cout
<< "asinh(1) = "
<< std::asinh(1) << '\n'
<< "asinh(-1) = "
<< std::asinh(-1) << '\n';
// special values
std::cout
<< "asinh(+0) = "
<< std::asinh(+0.0) << '\n'
<< "asinh(-0) = "
<< std::asinh(-0.0) << '\n';
}
asinh(1) = 0.881374
asinh(-1) = -0.881374
asinh(+0) = 0
asinh(-0) = -0