xref: /freebsd/lib/msun/man/atanh.3 (revision dc36d6f9bb1753f3808552f3afd30eda9a7b206a)

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.Dd June 9, 2013
.Dt ATANH 3
.Os
.Sh NAME
.Nm atanh ,
.Nm atanhf ,
.Nm atanhl
.Nd inverse hyperbolic tangent functions
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn atanh "double x"
.Ft float
.Fn atanhf "float x"
.Ft long double
.Fn atanhl "long double x"
.Sh DESCRIPTION
The
.Fn atanh ,
.Fn atanhf ,
and
.Fn atanhl
functions compute the inverse hyperbolic tangent
of the real
argument
.Fa x .
For a discussion of error due to roundoff, see
.Xr math 3 .
.Sh RETURN VALUES
These functions
return the inverse hyperbolic tangent of
.Fa x
if successful.
If the argument has absolute value 1, a divide-by-zero exception
is raised and an infinity is returned.
If
.Fa |x|
> 1, an invalid exception is raised and an \*(Na is returned.
.Sh SEE ALSO
.Xr acosh 3 ,
.Xr asinh 3 ,
.Xr exp 3 ,
.Xr fenv 3 ,
.Xr math 3
.Sh HISTORY
The
.Fn atanh ,
.Fn atanhf ,
and
.Fn atanhl
functions appeared in
.Bx 4.3 ,
.Fx 2.0 ,
and
.Fx 10.0 ,
respectively.