tanh(3) [php man page]
TANH(3) 1 TANH(3) tanh - Hyperbolic tangent SYNOPSIS
float tanh (float $arg) DESCRIPTION
Returns the hyperbolic tangent of $arg, defined as sinh(arg)/cosh(arg). PARAMETERS
o $arg - The argument to process RETURN VALUES
The hyperbolic tangent of $arg SEE ALSO
tan(3), atanh(3), sinh(3), cosh(3). PHP Documentation Group TANH(3)