                           HP 48 QEW Notes


        This is version 1.41 of my Quick Equation Writer.  It helps ease 
equation-solving, etc. on tests and pressure situations.  The program isn't 
too complex or speedy (ML would have been better but I only know RPL) but it 
does streamline operations.  When executed it displays a single algebraic 
symbol, the prompt "EQ:" and a menu of functions.  

{HOME}             PRG
----------------------
EQ:


'<-
*X   X  X^  *X^  (   )

        QEW is designed so you don't have to use alpha mode at all; I really 
hate all those keypresses.  So that's what all the "*X^" and such is for.  
Note that the commands ^( and SQ.RT( need closing ) parentheses to work.  The 
only command that works much differently is XROOT(.  The algebraic syntax for 
this command is:
                        XROOT(#,X)
where # is the root to be taken (three for cube root, etc.) and X is the 
variable.  So you must use the comma on the menu to enter an XROOT.  The comma 
isn't used for any other functions.
        The two commands QUIT and LOAD execute differently.  Quit is used with 
a clear algebraic prompt '.  Press QUIT and the screen will display 'QUIT.  
Press enter and QEW will exit without leaving stack garbage.  As for LOAD, it 
is entered the same way, with a clear algebraic prompt.  Press enter, and the 
prompt "Filename:" will appear, with a list of algebraic expressions in the 
current directory on the menu line.

{HOME}
----------------------
Filename:


'<-
EQ  EQ.1  EQ.2  MYEQ

  Some of these may not be equations; QEW doesn't sort for that.  Anyway, at 
the algebraic prompt, press the menu key for the filename and press enter.  
This equation will be loaded in the normal file entry mode, though the cursor 
will be placed at the end.
        Back to normal entry mode.  After you have typed in the equation, 
press enter.  The 48 will pause for a moment, then display a menu with the 
prompt "Select:"

{HOME}
----------------------
Select:
4:
3:
2:
1:
SOLV   PLOT       QUIT

        Selecting SOLV will take you to the solver.  PLOT will go to plotter 
and plot, with preset X and Y-ranges of:

              10
              |
              |
-20.5 --------+-------- 20.5
              |
              |
             -10

        Change these if you want; I find these good ranges for getting the 
general idea of things.  Remember, you can always zoom.
        The last command, QUIT, will return you to the stack without solving 
or plotting your equation.  But now, a word about the equation you typed in.  
Where does it go?  
        The answer is that entered equations are automatically saved as EQ.  
So as to preserve your old EQ, it moves the old one to EQ.1. If EQ.1 exists, 
it leaves EQ.1 the same and moves EQ to EQ.2.  This happens all the way up to 
EQ.9.  You probably don't want all these EQ's cluttering your directories up, 
so I suggest PURGEing from time to time.
        Perhaps the name "Quick Equation Writer" is misleading as it implies 
HP's graphic capabilities used in the real Equation Writer.  However, for 
real-world usage (though not to show off to friends -- "You paid $250 for 
THAT?!") it's a good little tool.  If you have any modifications or 
customizations, please add them in; but don't remove the credit line (my 
name) from the program.  I am currently a freshman at New Trier High School in 
Winnetka, Illinois, so I need all the recognition I can get.  

Credit to Eric Lin for the concept.

                                                
                                                Matt Caywood
                                                Wilmette, Illinois
                                                

