atanh, atanhf---inverse hyperbolic tangent Synopsis
#include <math.h> double atanh(double x); float atanhf(float x);
Description
atanh calculates the inverse hyperbolic tangent of x.
atanhf is identical, other than taking and returning
float values.
Returns
atanh and atanhf return the calculated value.
If
x|
is greater than 1, the global errno is set to EDOM and
the result is a NaN. A DOMAIN error is reported.
If
x|
is 1, the global errno is set to EDOM; and the result is
infinity with the same sign as x. A SING error is reported.
You can modify the error handling for these routines using
matherr.
Portability
Neither atanh nor atanhf are ANSI C.
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