Plotter V3.71
  © by Rüdiger Dreier 1988/9/90
  Plotter is FREEWARE.
  
  
  THE AUTHOR UNDERTAKES NO LIABILITY FOR ANY DAMAGE CAUSED BY THE APPROPRIATE
  OR NOT APPROPRIATE USE OF THIS PROGRAM !
  THE AUTHOR UNDERTAKES NO LIABILITY FOR THE FAULTLESSNESS OF THIS PROGRAM !
  USE IT AT YOUR OWN RISK !
  
  
  Tutorial:
  
  For those,  who do not understand my "clear"  description in the .DOC file,
  here is a short Tutorial:
  
  Let's say you want to plot the function sin(x)*cos(1.5*x) and discuss it.
  - Start the Plotter or you get problems to do the next things.
  - You  should see a blue  screen. Use the  mouse to look at  the menus. You
  should  find a menu  "change" with  10 subitems. There  are some predefined
  function.  Select one.  A  window  appears  with a  stringgadget.  In  this
  stringgadget  there should be  the function you selected  before. Delete it
  and  enter your new function.  Remember: always lower case  ! Press RETURN.
  The Window  should disappear, otherwise you should  check, whether you have
  closed all brackets again...
  - Look at the menu Change again.  There should be your new function now (or
  the first 14  characters of it) instead of the old  function. If you now go
  on the menu "Function", the same subitems appear. Select your function. 
  - The function  should appear on the  screen. GREAT ! But  you see that the
  function  is never greater than  0.91 or so. So  select the menu Intervall.
  Enter  for ymin  -0.91 and  for ymax  0.91. After  klicking on  OK your old
  function disappears. Let  it plot again (Select Function/yourfunction). Now
  it is better, isn't it ?
  - Now  discuss your function: Select  Discussion/yourfunction. The function
  disappears  and a message  appears that  the function is  discussed for the
  intervall -3.141|3.141.
  - The  program will find  5 points where  the function is  zero, 6 extremas
  (Min/Max) and  5 turning points. And the  first and second differentiations
  are displayed.
  
  - To quit the program, select Quit. A requester appears to ask you, whether
  you really want to quit. Select Quit.
  
  READY