Functions and CALL Routines 
Returns the inverse hyperbolic tangent.
 x

specifies a numeric constant, variable, or expression.
The ARTANH function computes the inverse hyperbolic tangent.
The ARTANH function is mathematically defined by the following equation, where 1
< x< 1:
The following example computes the inverse hyperbolic tangent.
data _null_;
x=artanh(0.5);
put x=;
run;
SAS writes the following output to the log:
x=0.5493061443
Copyright © 2011 by SAS Institute Inc., Cary, NC, USA. All rights reserved.