atanh, atanhf, atanhl
The new home for Visual Studio documentation is Visual Studio 2017 Documentation on docs.microsoft.com.
The latest version of this topic can be found at atanh, atanhf, atanhl.
Calculates the inverse hyperbolic tangent.
double atanh( double x ); float atanh( float x ); // C++ only long double atanh( long double x ); // C++ only float atanhf( float x ); long double atanhl( long double x );
Parameters
x
Floating-point value.
The atanh functions return the inverse hyberbolic tangent (arc hyperbolic tangent) of x. If x is greater than 1, or less than –1, errno is set to EDOM and the result is a quiet NaN. If x is equal to 1 or -1, a positive or negative infinity is returned, respectively, and errno is set to ERANGE.
| Input | SEH Exception | Matherr Exception |
|---|---|---|
| ± QNAN,IND | none | none |
X ≥ 1; x ≤ -1 | none | none |
Because C++ allows overloading, you can call overloads of atanh that take and return float or long double values. In a C program, atanh always takes and returns double.
| Function | C header | C++ header |
|---|---|---|
atanh, atanhf, atanhl | <math.h> | <cmath> |
For additional compatibility information, see Compatibility.
// crt_atanh.c
// This program displays the hyperbolic tangent of pi / 4
// and the arc hyperbolic tangent of the result.
//
#include <math.h>
#include <stdio.h>
int main( void )
{
double pi = 3.1415926535;
double x, y;
x = tanh( pi / 4 );
y = atanh( x );
printf( "tanh( %f ) = %f\n", pi/4, x );
printf( "atanh( %f ) = %f\n", x, y );
}
tanh( 0.785398 ) = 0.655794 atanh( 0.655794 ) = 0.785398
Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.
Floating-Point Support
Long Double
acos, acosf, acosl
asin, asinf, asinl
atan, atanf, atanl, atan2, atan2f, atan2l
cos, cosf, cosl, cosh, coshf, coshl
sin, sinf, sinl, sinh, sinhf, sinhl
tan, tanf, tanl, tanh, tanhf, tanhl
_CItan