text: /*	@(#)tanh.c	4.1	12/25/82	*/
  
  /*
  	tanh(arg) computes the hyperbolic tangent of its floating
  	point argument.
  
  	sinh and cosh are called except for large arguments, which
  	would cause overflow improperly.
  */
  
  double sinh(), cosh();
  
  double
  tanh(arg)
  	double arg;
  {
  	double sign;
  
  	sign = 1.;
  	if (arg < 0.) {
  		arg = -arg;
  		sign = -1.;
  	}
  
  	if (arg > 21.)
  		return (sign);
  
  	return (sign * sinh(arg) / cosh(arg));
  }
  