Command: tan
  
Syntax: 
  x2 = tan(x1) 
  
Description: 
  Return the tangent of x1, where x1 is in radians.
  
Comments: 
  This function may be applied to an atom or to all elements
  of a sequence.
  
Example: 
     t = tan(1.0)
       -- t is 1.55741
     
See Also: 
  sin, cos, arctan
  
