atanh() returns the hyperbolic arc tangent of x for x in the
interval (-1,1). atanh() is the inverse function of tanh().
atanh(tanh (x)) = x.
atanh(x) is computed as 1/2 ln((1+x)/(1-x)).
Entry-Point Names
Generic
Function Data Type OpenVMS Tru64 UNIX
Name Required
atanh S_FLOAT math$atanh_s atanhf
T_FLOAT math$atanh_t atanh
X_FLOAT math$atanh_x atanhl
F_FLOAT math$atanh_f
G_FLOAT math$atanh_g