                                           Calc3a
        Scientific Calculator for Psion Series 3a
                     (c) Alfa Computing 1995-1996
                                  Richard Schmidt
                       Richard Sturenberghlaan 50
                                2273 GX  VOORBURG
                            THE NETHERLANDS (EUR)
                  Email @ Compuserve : 100735,331
       Email @ Internet : rschmidt@worldonline.nl
  Homepage : http://www.worldonline.nl/~rschmidt/   
                                                 
                                   Version V1.6.1
                                         09/12/96


Index
=====
1.     INTRODUCTION
2.     INSTALLING CALC3A
2.1    DISTRIBUTION
2.2    HOW TO INSTALL
2.3    REQUIREMENTS
3.     GENERAL
3.1    CALCULATOR MAIN SCREEN
3.2    USING HELP
3.3    USING MENUS
3.4    PREFERENCES
4.     CALCULATIONS
4.1    GETTING STARTED
4.2    FUNCTIONS
4.2.1  Functions with two results
4.2.2  Functions with temporary results
4.2.3  Percentage calculations
4.3    CALCULATION EXAMPLES
4.4    MEMORIES
4.4.1  Statistics memories
4.4.2  Calculator memories
4.4.3  Recall buffer
4.4.4  Export of memories
5.     EQUATIONS
5.1    THE EQUATION DATABASE
5.2    INPUT OF EQUATIONS
5.3    DELETE EQUATIONS
5.4    EVALUATING EQUATIONS
6.     SOLVER
6.1    THE EQUATION DATABASE
6.2    SOLVING EQUATION
7.     XY PLOT
7.1    PLOT SETTINGS
7.2    EXECUTE XY PLOT
7.2.1  Trace mode
8.     CONSTANTS
9.     INTEGRATE
10.    FRACTIONS
11.    EXTERNAL MATH FUNCTIONS
12.    THE AUTHOR
12.1   HOW TO CONTACT THE AUTHOR
12.2   DISCLAIMER
12.3   HOW TO REGISTER
13.    APPENDICES
13.1   FUNCTION REFERENCE
13.2   KEYBOARD REFERENCE
13.3   WITH SPECIAL THANKS TO ...
14.    HISTORY
15.    ADDONS
16.    EQNCONV


1. Introduction
===============
Welcome to Calc3a!
Calc3a is a scientific calculator for the Psion 
Series 3a. It operates similar to a CASIO(c) FX 
or SHARP(c) style calculator and has 
approximately 60 built-in math functions. Calc3a 
has been set up to be just like a physical 
calculator. It has an LCD display and tiny buttons 
which can be accessed with single keystrokes.

Features of Calc3a:
- basic, scientific, programmer and statistics 
  calculations;
- hexadecimal, binary and octal conversions/
  calculations.
- graphical XY plots;
- equation database;
- equation evaluator;
- constants list;
- integrate;
- fraction tool;
- 26 memories, statistics memory and 
  recall buffer;
- solver for single unknown variable in an 
  equation;
- support for external math functions in OPL.

Calc3a is only available in English for the Psion 
Series 3a.

2. Installing Calc3a
====================
Before using the Calc3a application you should 
install it from your PC to your Psion. 

2.1 Distribution
================
An unregistered copy of this application may be 
distributed freely. The Calc3a application itself 
consists of the following files:

CALC3A.OPA     Main application 
CALC3A01.RSC   Help screens
CALC3A02.RSC   Equation evaluator module
CALC3A03.RSC   XY Plot module
CALC3A04.RSC   Application resources
ADDON.OPL      Example code for external math 
               functions
ADDON.OPO      Compiled version of ADDON.OPL
CALC3A.EQN     Database with example equations
               only for use with decimal 
               separator set to period.
MANUAL1.TXT    This manual part 1
MANUAL2.TXT    This manual part 2                     
EQNCONV.OPO    Utility to convert period based
               equation database to a comma one

2.2 How to install
==================
To install Calc3a:

- copy file CALC3A.OPA to an \APP directory on 
  any disk
- copy files CALC3A01.RSC, CALC3A02.RSC, 
  CALC3A03.RSC and CALC3A04.RSC  to an 
  \APP\CALC3A directory on any disk. 
- optionally copy file ADDON.OPO to an \OPO 
  directory and ADDON.OPL to an \OPL directory on 
  any disk. This is only needed when you want to 
  add you own math functions to the program. 
- optionally copy file CALC3A.EQN to an \OPD 
  directory on your default disk. This is only 
  needed when you want to use/try the enclosed
  example equations and has a period selected
  as decimal separator (in the system screen).
  When a comma is selected as a decimal 
  separator, copy file COMMA.EQN to an \OPD 
  directory on your default disk and RENAME it 
  to CALC3A.EQN !
  If you already added you own equations to the
  database, use EQNCONV to convert it.
- Install the Calc3a application in the system 
  screen by pressing Psion-I.

Make sure you have an \OPD directory on your 
default drive. Calc3a will save its 
configuration to \OPD\CALC3A.INI. 

2.3 Requirements 
================
The application requires 90K RAM memory and 
approximately 80K ram of disk space. If your 
machine appears to be out of memory try to close 
a few applications or erase files from internal 
memory (after making a backup first!).

3. General
==========

3.1  Calculator main screen
===========================
After the application has been launched from the 
system screen, the calculator main window 
appears. The patterned grey bar on the top of the 
screen contains two 'LCD displays'. 

The left LCD display shows us the calculator 
modes and the contents of the active memory. The 
modes can be changed by keyboard or from the 
pull-down menus.

Mode                Description
--------------------------------------------------
Page         PAGE_A First page with 60 buttons
             PAGE_B Second page with 60 buttons
             PAGE_C Third page with 60 buttons
                    (external functions) 

Calculation  COMP   Compute mode, scientific 
                    calculations
mode         SD     Statistics mode
             LR     Linear regression mode

Trigonometr. DEG    Trigonometric. calculations 
                    with degrees
mode         RAD    Trigonometric. calculations 
                    with radians

Format       GEN    General format base-10 numbers
             SCI    Scientific format e.g.1.0E-12
             FIX    Fixed format, fixed number of 
                    decimals
             HEX    Hexadecimal format base-16 
                    numbers
             BIN    Binary format base-2 numbers
             OCT    Octal format base-8 numbers
             ENG    Engineering mode E-12 .. E12
                    (temporary mode)

Contents of active memory MA..MZ Memory 1 (A) up 
to memory 26 (Z)

There are three keys available to switch these 
modes:
- Psion-C, to alter calculation mode;
- Psion-T, to alter trigonometric mode;
- Psion-F, to alter display format;
- Shift-Psion-F, to alter display format in
  reverse order.
Press these keys repeatedly to select the desired 
mode.

To change directly to a base-n mode there are 
four shortcut keys available:
- Psion-D switch/convert to decimal (base-10)mode;
- Psion-H switch/convert to hex (base-16) mode;
- Psion-O switch/convert to octal (base-8) mode;
- Psion-B switch/convert to binary (base-2) mode;

The last result or typed-in number on the LCD 
screen will then automatically be converted to 
the selected base-n equivalent. These four 
shortcuts are also available in the menus. Press 
the Menu key to display the top level menu.

The calculator has 26 memories to store numbers 
and intermediate results. These memories are 
called `MA' to `MZ'. The contents of the active 
memory is always displayed on the left LCD. To 
switch between these 26 memories press Control 
and the memory identification character. e.g. 
Control-C will select memory 3 (MC) and the 
contents of this memory is displayed on the left 
LCD. Please refer to chapter `Memories' to learn 
more about these memories.

The right LCD display shows us calculation 
results and numbers typed in by the user. If the 
format is set to hexadecimal, binary or octal, 
the displayed numbers are succeeded by a single 
character where `b' stands for binary number, `o' 
stands for octal number and `h' stands for 
hexadecimal number. Negative numbers are preceded 
by a negative (-) sign.

All buttons are displayed below the LCD 
displays. Because of the large number of  buttons, 
they are divided over two pages. To switch 
between the two pages press PgUp and PgDn.

3.2 Using help
==============
Press the Help button to bring up the help 
index. Select an item you want to know more about 
and press Enter. Press Esc to leave help and to 
return to the main screen.

3.3 Using menus
===============
Press the Menu key to display the top level menu. 
The plot module, equation database manager and 
the main calculator application all have 
different menus.

3.4 Preferences
===============
The preferences can be changed by bringing up the 
`Set preferences' menu.  This menu can be 
accessed by pressing Psion-Q and has three items 
`Keyboard', `Display' and `Modes'. After changing 
the preferences they will be saved to disk.

Format
Select between display formats. There are six 
formats available. The formats can also be 
selected by pressing Psion-F or Shift-Psion-F
repeatedly. The formats HEXadecimal, OCTal, 
BINary and GENeral can also be selected by 
pressing the hot keys (Psion-H, Psion-O, Psion-B 
and Psion-D) for these formats.

Decimals
Number of decimals to show for numbers on the 
display. Press Tab repeatedly to select between 0 
and 20 decimals.
Be aware that the number of decimals applies to
- representation of numbers on calculator display;
- representation of numbers in solver dialog;
- representation of numbers in evaluator dialog;
- representation of numbers in fractions dialog;
- representation of numbers in integrator dialog.

Trigonometric calculations
Select between trigonometric calculations with 
degrees or radians. Math functions like SIN, TAN, 
etc. require this mode to be set correctly.

Calculation mode
Select between three different calculation modes:
LR    Linear regression mode, requires single 
      numbers as data;
SD    Statistics mode, requires X,Y pairs of 
      data;
COMP  Compute mode, usage of all scientific 
      functions.

Extra help mode
To display a help line after each calculation is 
executed set this field to `On'. Immediately 
after you have pressed Enter or = or an unary 
function a help line is displayed in the lower 
right corner of the screen. When the `Display 
extra help' is set to yes, all dialog boxes used 
for  entering equations will show the equation 
constraints.
For clear display of large numbers the 'Display
thousends separator' must be set to yes. 

Decimal separator
Select a comma or period as a decimal separator. 
If the decimal separator has been altered, the 
keyboard layout on the screen will be updated. 
This setting must be equal to the one you set in 
the system screen. So if you have chosen a 
period as decimal separator in the system screen 
(number format Shift-Psion-F) please select a 
period in Calc3a application too!

***********************************************
To use the example equation database in 
combination with the comma as separator, copy
COMMA.EQN to \OPD\CALC3A.EQN. 
***********************************************

To separate X- and Y-data in LR memory use the 
period in case you use the comma as decimal 
separator. Use the comma to separate if you use 
the period as decimal separator.

Alternative keyboard
This option is only for users that have a Psion 
with a German keyboard layout. This option swaps 
some keys:

Function Non German German
--------------------------
PI       ~          z
`"o      `          Q
MIN      ^          M

Parenthesis
Mode for closing parenthesis. Options are:
- calculate on close;
- wait for <Enter>.

4. Calculations
===============

4.1 Getting started
===================
After the application has been launched from the 
system screen, the calculator main window 
appears. The patterned grey bar on the top of the 
screen contains two 'LCD displays'. 

The left LCD display shows the trigonometric mode 
(DEG or RAD), the calculation mode (SD, LR or 
COMP), the format used to display numbers 
(SCIentific, GENeral, FIXed, ENGineering,
HEXadecimal, BINary or OCTal) and the contents 
the active memory M. 

The right LCD display shows results of 
calculations and numbers typed in by the user. 
All calculator buttons can be 'pressed' with 
single keystrokes. Each button is preceded by a 
single upper or lowercase character. This 
character can be used to activate a button and 
thus a math function.

Calculations are performed just as you would with 
a stand-alone calculator. Examples (<k> equals to 
keystroke 'k')

Square root of 25    : 25<r>
10 to the power of 3 : 3<L>
2 to the power of 5  : 2<x>5<=>
Mean of 4,8,9,3,2    : 4<@>8<@>9<@>3<@>2<@><\>
25 div 4             : 25<d>4<=>                          
150+17.5%            : 150<+>17.5<%>
10% of 1000          : 1000<*>10%

While typing in a number, press Delete to erase 
the last digit typed . Esc clears all input. Press 
the Help key in the Calc3a application to read 
more about the usage of Calc3a.

4.2  Functions
==============
The calculator has approximately 60 built-in 
functions. There are two types of functions:

1.Unary
Function applies to one number e.g. Square root of 
x or Sine of x To perform an unary calculation, 
first type in a number, than press a unary 
function button. The result of this calculation 
is shown at the right LCD display.

2.Binary
Function applies to two numbers e.g. 5+6 or x to 
the power of y. To perform a binary calculation, 
first type in the first number, than press a 
binary function button (operator). Type in the 
second number and press Enter. The result of this 
calculation is shown at the right LCD display.

4.2.1 Functions with two results
================================
Some functions like POL() and REC() return two 
results. After pressing the Enter key the result 
of such a function will be shown at the lower 
right corner of the screen for about two seconds. 
The first result will also be shown at the 
calculator LCD display. The second result is 
stored in the recall buffer and can be accessed 
by pressing the left-arrow key once.

4.2.2 Functions with temporary results
======================================
The function o`" (conversion degrees to 
degrees-min-sec) returns a number in the form 
of `degrees-minutes-seconds'. The result of 
such a function will be displayed on the LCD 
display until a key is pressed.

Please refer to appendix `functions' for more 
about available math functions.

4.2.3 Percentage calculations
=============================
Calc3a allows for simple percentage calculations:
- add percentage;
- subtract percentage;
- calculate percentage.
 
A percentage calculation takes the following form:
<Amount><Operator><Percentage><%>
 

Operator/Description      Example
--------------------------------------------------
+  Add percentage   100+15% >> 100<+>15<%> 115
-  Subtract perc.   50-17.5% >> 50<->17.5<%> 41.25
*  Calculate perc.  10% of 1000 >>10<*>1000<%> 100

4.3  Calculation examples
=========================
Below are some examples of several types of 
calculations. Every example consists of three 
parts:
1. Description of example
2. Math notation
3. keyboard strokes to perform calculations.
   Do not type the '<' and '>' characters.

Square root of 100 
SQR(100)
100<r>

Logarithm of 1000 
LOG(1000)
1000<l>

Convert 10,50 polar to rectangular
REC(10,50)
10<P>50<Enter>

17.5% of 50
50*17.5%
50<*>17.5<%>

100 plus 50%
100+50%
100<+>50<%>

2 to the power of 8
2^8
2<x>8<Enter>

2 to the power of 8
2^8
8<y>

-1.0*5
NEG(5)
5<_>

Reciprocal value of sine of 50
1/SIN(50)
50<s><i>

Mean of 4.5, 6.7, 2.9 and 6.7
MEAN(4.5, 6.7, 2.9, 6.7)
Set calculator to SD mode 
<Shift-Esc> (clear stat memory) 
4.5<@>6.7<@>2.9<@>6.7<@><\>

Correlation factor r of
10,12
11,15
12,18
14,16 
r(data)
Set calculator to LR mode 
<Shift-Esc> (clear stat memory)
10<,>12<@>
11<,>15<@>
12<,>18<@>
14<,>16<@>
<v>

Convert 50 decimal to binary
BIN(50)
<Psion-D>
50
<Psion-B>

e (2.71....)
EXP(1)
1<N>

5-BASE log of  10
5LOG(10)
5<,>10<Diamond-key><g>
Function gLOG(x) is an external function in 
ADDON.OPO. External functions require the 
operands to be separated with a comma (or point 
for German users).

4.4 Memories
============

4.4.1 Statistics memories
=========================
The program allows for statistics calculations. A 
maximum of 1000 numbers can be stored in this 
statistics memory to be used for calculations in 
SD mode. Also 1000 x,y numbers can be stored in 
this memory when performing LR calculations. It 
is possible to change numbers in the statistics 
memory. Press Psion-Y to bring up the `Edit 
statistics memory' dialog. Press the left-arrow 
and right-arrow keys to scroll through all 
numbers in statistics memory. A message will be 
shown if the statistics memory does not contain 
numbers.

After changing one or more numbers in statistics 
memory all statistic functions will use these new 
numbers.

4.4.2 Calculator memories
=========================
Calc3a has 26 memories called MA..MZ. The M+ 
(Psion-+) and M- (Psion--) buttons can be used to 
store numbers into these memories. These memories 
have an initial value of 0. The current value of 
the active memory M is displayed on the top left 
LCD display.

Press Psion-E to change the contents of one of 
the memories. Use the left-arrow and right- arrow 
key to select a memory to modify.

4.4.3 Recall buffer
===================
The application maintains a 'recall' buffer. Each 
entered number and calculation result will be 
stored to this recall buffer. Press Psion-S to 
scroll through all previously entered numbers. To 
recall a previously entered number or result 
press the left arrow or right arrow key. The 
numbers will appear on the calculator LCD. The 
recall buffer has room for 50 numbers.

4.4.4 Export of memories
========================
The contents of the memories, statistics memory 
and recall buffer can be exported to a plain text 
file. Press Psion-G to bring up the `Export' 
dialog. It possible to select the export of: - 
memories A..Z and/or - statistics memory and/or - 
recall buffer.

The contents of the different memories are 
written to a single text file. These files can be 
used to import into a spreadsheet. A typical export 
to text file looks like:

Memories A-Z		
100.45
0
.
.
0
44.8
0
Statistics memory
15,30
45,80
60,100
Recall buffer
15
30
0
.
.
0
45
80
66
2.01515152
2.01515152
1.41956032

5. Equations
============
Calc3a allows for entering equations. These 
equations are stored in a database called 
\OPD\CALC3A.EQN. Equations in this database can 
be evaluated or solved.

5.1 The equation database
=========================
It is possible to set up a database with all your 
frequently used equations and conversion 
formulas. Each equation is stored with a 
description (max 30 characters). The equation 
database manager (EDM) shows up each time you 
want to evaluate or solve an equation. 

The top frame of this dialog displays the number 
of equations currently stored in the database and 
the equation itself. This equation line is 
updated each time you move the cursor over a new 
equation.

The lower area of the dialog shows four buttons. 
The `Evaluate' button is replaced by a `Solve' 
button when solving equations. Keys available in 
the EDM:

Up            Move cursor one row up
Down          Move cursor one row down
Pg-Up         Move cursor one page up
Pg-Dn         Move cursor one page down
Home          Move cursor to first equation
End           Move cursor to last equation
E or Psion-E  Enter equation/description 
              selected with cursor
D or Psion-D  Delete equation selected with cursor
or Delete
U or Psion-U  Enter new equation
V or Psion-V  Evaluate equation
or Enter
S or Psion-S  Solve equation
or Enter
MENU          Bring up the equation database 
              main menu
X or Psion-X  Exit equation database and return to
or Esc        main calculator
F or Psion-F  Search for equation. Searches from 
              current cursor position to end of 
              database. Search is case sensitive.
G or Psion-G  Find next occurrence  

5.2 Input of equations
======================
Press Psion-U from the main calculator screen to 
bring up the equation database. Select an 
equation with the selection bar (cursor) and 
press U or Psion-U to modify an equation or E or 
Psion-E to enter a new equation.

The `Equation evaluator' dialog has two fields. 
One is for the short description (30 characters) 
used as an identification for the equation. The 
`Equation' field contains the equation itself. 
This equation may be 255 characters long.

[Notice the constraints!]

In equations you can use:
- Variables with names that only contain (a 
  maximum of 12) alphabetical characters. The 
  length of variable names is limited to 10 
  characters and must be entered lowercase; 
- All OPL math functions as mentioned in the 
  Psion programming manual, function names must 
  always be entered uppercase; Parenthesis; 
- Trigonometric functions, radians/degrees 
  depending on settings in system screen.

Available functions/constants for equations:
ABS(x)    LN(x)     EXP(x)      +
ACOS(x)   LOG(x)    SIN(x)      -
ASIN(x)   MAX(a,b)  SQR(x)      *
ATAN(x)   MEAN(a,b) STD(a,b)    /
COS(x)    MIN(a,b)  TAN(x)      5E-5
DEG(x)    RAD(x)    SUM(a,b)    x**y
INTFx)    RND       VAR(x)

5.3 Delete equations
====================
Press Psion-U from the main calculator screen to 
bring up the equation database. To delete an 
equation just move the cursor over the equation 
and press Delete, Psion-D or just D.

5.4 Evaluating equations
========================
Press Psion-U from the calculator main screen to 
evaluate an existing equation. Select an equation 
from the EDM and press V or Psion-V to execute 
the evaluator. The Variables/result' dialog is 
shown on screen. All the variables used in your 
equation will be shown in this dialog. If you 
used more than four variables in your equation 
use the left-arrow and right-arrow key to 
view/enter the other variables. 

Enter the contents of the variables and press 
Enter. The result will be displayed in the same 
dialog on the last line. To repeat an evaluation 
just change a variable when desired and press 
Enter.

If the equation was not entered correctly 
(missing parenthesis, missing operators) a 
message will be shown on screen and the result 
will equal to 0.

6. Solver
=========

6.1 The equation database
=========================
The solver uses an equation from the equation 
database. Please refer to chapter 5.1 for more 
information about the equation database manager. 
The solver allows for solving a single unknown 
variable in an equation. Therefor it uses method 
`Secant' to find a single solution.

6.2 Solving equation
====================
Press Psion-L from the calculator main screen to 
solve an existing equation. Pick an equation from 
the EDM and press S or Psion-S to start the 
solver.

The Variables/result' dialog is shown on screen. 
Enter the values of the known variables. If you 
used more than four variables in your equation 
use the left-arrow and right-arrow key to 
view/enter the other variables. The variable to 
be solved can be set to zero.

Press Enter to bring up the solver settings 
dialog.

Unknown variable to solve
Press Tab on this field to view all variables 
used in your equation. Select the variable to be 
solved from the list.

Tolerance
Tolerance in the result of the solving process. 
The smaller the tolerance the more accurate 
answers you get.

Maximum number of iterations
Maximum number of iterations to find the result.

Initial guess1/guess2
Two possible values for the unknown variable. 
These two guesses form a X-range for the solver. 
Please select an range as narrow as possible to 
get accurate answers. The solver can be started  
by pressing Enter. After a few seconds (depending 
on the complexity of the equation) the result is 
shown in the Variables/result dialog. If an error 
occurs during the solve process  the result will 
always equal 0. 

Note : Guess1<Guess2

7. XY plot
==========
Two functions can be plotted on the screen at a 
time. After the functions have been plotted it is 
possible to move a cursor around the screen to 
determine points of intersection.

7.1 Plot settings
=================
The plot settings must be set before making a 
plot. Three dialogs will lead you through the 
plot settings. All plot settings will be saved to 
disk automatically. The first dialog is for 
setting the axis options.

Scale
It is possible to select a linear or logarithmic 
scale for the X-axis and Y-axis. Only positive 
logarithmic scales are allowed for.

X tick/Y tick
A tick is a position marker on the axis. Tick can 
be used for measuring and can only be used in 
linear scaled plots. In logarithmic plots the 
tick will be determined automatically.

Show labels in X-direction/
Show labels in Y-direction
Use this option to show values along the X- and 
Y-axis. Labels can be plotted above or below the 
X-axis and to the left or right of the Y-axis.

Show grid lines
Grid lines are lines drawn on each tick on the 
axis and can also be used for measuring.

Show intersection points
Use this option to plot a point on all evaluated 
X,Y position.

Plot line between intersection points
Use this option to plot a line between the 
evaluated X,Y points.

The second dialog is used to set the plot range

Xmin, Ymin, Xmax, Ymax
Range for XY plot. These values are used for :
- drawing the axis;
- a range for x necessary to evaluate the 
  function.

X step evaluator
Step for x to evaluate the equations. So if the 
range is set from -5 to 5 and step is set to 0.5 
the equation will be (5--5)/0.5 = 20 times 
evaluated. The following points will be 
calculated : f(-5), f(-4.5), f(-4), f(-3.5), 
f(-3), f(-2.5) .. f(5). The step value must be in 
range 0.001-1000.

The third dialog queries two equations.

Function f(x)/g(x)=
The equation for plotting. Two functions can be 
plotted at a time using the same scale. The 
equations may be 30 characters long. 

In equations you can use:
- Only variable `x' (lowercase) can be used in 
  equations;
- All OPL math functions as mention in the Psion 
  programming manual, function names must always 
  be entered uppercase;
- Parenthesis;
- Trigonometric functions, radians/degrees 
  depending on settings in system screen.

To plot only one function leave the other 
  function field blank. If the equation was not 
entered correctly (missing parenthesis, missing 
operators) it will be drawn as f(x)=0. 

Plot
This dialog also allows for selecting f(x) and/or 
g(x) from the equation database. Use tab to 
select between selecting only f(x) and/or g(x) or 
plot functions as specified in the f(x) and g(x) 
fields. The EDM dialog appears for selecting an 
equation when you choose to select at least one 
equation. Insure that the selected equation 
contains only one variable named 'x' for correct 
plotting.

See "equations" for available functions.

7.2 Execute XY plot
===================
Press Psion-K to plot the two functions according 
to the plot settings. 

The cursor can be used to determine intersection 
points or points on the graphs. To move this 
cursor around:
Left                 move cursor to left
Right                move cursor to right
Control-Left         move cursor to left in 
                     big steps
Control-Right        move cursor to right in 
                     big steps
Shift-Control-Left   move cursor to left in 
                     huge steps
Shift-Control-Right  move cursor to right in 
                     huge steps
Psion-+              Enlarge visor
Psion--              Reduce visor

Press any key to interrupt plotting.

Press Menu to display the top level menu of the 
plot module. Psion-J can be used to alter plot 
settings. To redraw the plot with new settings 
press Psion-K. To return to the calculator main 
screen press Psion-X or Esc.

7.2.1 Trace mode
================
The cursor can be set to `Trace' function f(x)
or function g(x). 
Each time the cursor is moved in the X- 
direction, the program recalculates F(x) and 
positions the cursor on the calculated Y- 
position on the curve. 

8. Constants
============
Calc3a allows for 10 numeric constants to be 
defined. Press Psion-I to bring up the constants
dialog. First select the constant (C0..C9) to 
edit or paste. 
Select paste to paste constant to calculator, use
edit to modify selected constant.

9. Integrate
============
This function can be used to integrate functions
according to simpsons rule. 

After pressing Psion-N two dialogs are presented.
The first dialog allows for entering f(x)dx.
It is also possible to select an equation from 
the equation database. Use tab on the second field
to select between f(x)dx as specified in the 
f(x)dx field or selecting an equation from 
database. 

In case of selecting from database the EDM dialog 
appears. Insure that selected equation contains 
only one variable named 'x' for correct 
integrating.

Secondly the 'integrate - result' dialog is shown 
on screen. 

Number of samples
Number of samples to be used for calculating 

X min/X max
Range for integrating f(Xmin) .. f(Xmax)

The integrator can be started by pressing Enter. 
After a few seconds (depending on the complexity
of the equation) the result is shown in the 
'Integrate - result' dialog.

Note : X max>X min

10. Fractions
=============
Calc3a allows for adding and subtracting 
fractions. Fractions can be entered like:
'1/1/3' equals one and one third
'3/4' three quarters
'/6' one fifth

After entering two fractions select the 
operator (+ or -) and press enter. The
result will be shown on the bottom line
of the dialog.

Pressing escape returns to the main calculator
screen displaying the result as a division.

11. External math functions
==========================
The Calc3a application allows for external math 
functions to be accessed in a OPO file. Enclosed 
with this package is an example OPL file that 
illustrates the use of external OPL functions. 
In this file the procedure `Register()' must 
always be available. This function is used by 
Calc3a to determine what functions are available 
in the external OPO file and what hotkey must be 
used to access that particular function. There 
are several procedures available for interfacing 
with the Calc3a application. So, for each added 
function you must add a RegFunc- entry to the 
`Register()' procedure.

Please read ADDON.OPL for more information

To access an external function from within the 
calculator:
- Press the diamond key;
- Press the hotkey.

External functions may contain all OPL commands 
including dialogs. Please refer to ADDON.OPL for 
more information. If this information is 
insufficient, contact the author for more 
information about using external functions.

Press Psion-Z or select PAGE_C to view all 
external functions.

12. The author
==============

12.1 How to contact the author
==============================
The author can be reached by mailing to:
Alfa Computing
Richard Schmidt
Richard Sturenberghlaan 50
2273 GX  VOORBURG
THE NETHERLANDS (EUR)
Email @ Compuserve : 100735,331

<<PREFERRABLE>>
Email @ Internet : rschmidt@worldonline.nl
Homepage : http://www.worldonline.nl/~rschmidt/
(check out this home page for the latest versions)

12.2 Disclaimer
===============
The author takes no responsibility for any lost 
data or hardware malfunctions of any kind due to 
the use of this software or any other software 
that ships with Calc3a.

12.3 How To register
====================
The cost for this application is:
$10      [US]
5-10    [UK]
Hfl 20,= [NL]
DM 20,-  [DU]
Fr 60,-  [FR]

- send cash in envelope to my postal address or
- use SwReg on compuserve to register 
  SWReg id : 7171
  Product  : Calc3a or
- Only for Dutch users 
  Stort voor registratie Hfl 20,-- op 
  girorekening 6338889 tnv R.G.Schmidt
  te Voorburg o.v.v. uw adresgegevens.


13. Appendices
==============

13.1 Function reference
=======================
+dB - add dB (decibel) - UC - B
1/X - reciprocal of x - UC - i
10^X - ten to the power of x - UCO - L
2^X - two to the power of x - UC - y
A - constant term of regression a - KL - A
ABS - absolute of x - UCO - a
ACOS - inverse cosine of x - UCO - C
AND - logical AND - UC - G
ASIN - inverse sine of x - UCO - S
ATAN - inverse tangents of x - UCO - T
B - regression coefficient b - KL - W
COS - cosine of x - UCO - c
COSH - hyper cosine of x - UCO - h
COTG - cotangents of x - UC - g
dB - convert to decibel - UC - D
DEG - convert radians to degrees - UC - J
DIV - integer division - BC, - d
EXP - e to the power of x - UCO - N
Erg - convert to energetic - UC - E
EX - sum of x - KSO - u
Ex^2 - sum of square of x - KS - U
FRAC - fractal part of x - UC - f
INT - integer part of x - UCO - I
LN - natural logarithm of x - UCO - n
LOG - logarithm of x - UCO - l
MAX - lowest value of x - KSO - &
MEAN - mean of x - KSO - \
MIN - lowest value of x - KSO - ^ or M
MOD - modulo - BC - m
n - number of statistics data in memory - KS - ;
nCr - combinations - BC - o
nPr - permutations - BC - O
NEG - negative - UC - _
NOT - logical NOT - BC - F
`' '' - convert to degrees-min-sec - UC - ' or Q
OR - logical OR - UC - H
PI - pi 3.14... - KCO - ~ or z
Pol - convert to polar - BC - p
r - correlation of x,y - KL - v
RAD - convert degrees to radians - UC - K
Rec - convert to rectangular - BC - P
RND# - random number between 0 and 1 - KCO - #
SIN - sine of x - UCO - s
SINH - hyper sine of x - UC - j
SQR - square root of x - UCO - r
STD - standard deviation of x - KSO - [
SURF - calculate surface in LR memory - KL - Z
TAN - tangents of x - UCO - t
TANH - hyper tangents of x - UC - k
VAR - variation of x - KSO - V
X! - factorial of x - UC - !
X^ - estimate x - UL - X
X^Y - x to the power of y - BC - x
XSQR - x th root of y - BC - q
X^2 - square of x - UCO - R
Y^ - estimate y - UL - Y
XOR - logical XOR operation - UC - w
<- - convert degrees-min-sec to degrees - UC - b

Characteristics: 
U = unary function 
B = binary function 
C = available in COMPute mode
L = available in LR mode
S = available in SD mode
O = standard CALC/OPL function
K = constant (no argument)

