Overview

EasyCalc is a graphing, scientific calculator for Palm's and PalmPilots. Of course it has all the capabilities and ease-of-use of the built-in "4-Banger" that comes with the PalmPilot, but also includes trigonometric functions, financial functions, complex numbers and graphing. In addition, you can define your own functions and variables with names up to 10 characters long and nesting up to ten levels deep. Values may range between 1E-100 and 1E250.

Other features:

Multiple screens easily categorize functions
"ANS" button recalls last result
Scroll-able history
Scrolling list for functions
Zoom-in and Zoom-out for graphs
Plot multiple functions at a time
User definable axis
Radian, Degree or Grad mode
Hex, Decimal, Binary or Octal computing modes
Normal, Scientific or Engineering output modes
User selectable precision to 15 digits
Automatic match for brackets
Full clipboard support
Complex numbers
Normal, polar and parametric graphs with support for tracing the graphs and table mode
Support for color palms
and many more coming in future versions..

Installation

I received many emails from you that you cannot find graphs in EasyCalc. You will now find 3 programs in EasyCalc ditribution. These 3 programs are completely exchangable, but they do not do the same. The largest one, calc_all.prc (over 110K) contains all features (graphs and special functions). File calc_graph.prc doesn't contain special functions but contains graphs. And file calc_small.prc contains neither graphs nor special functions (it is abou 70K). Install only ONE of these programs. Every new installation of any of these program will rewrite the previously isntalled one.

Basic calculations

Let's start with something very simple. After starting the calculator, you should see something like this:
Basic screen

And now let's compute a very simple thing: 3+3=6. Type in '3+3' using either the buttons on the screen or graffiti and press 'EXE' or write the newline graffiti. '6' will appear in the result area. And now to something more complicated - let's compute '3*sin(pi/2)'. First change to the 'Scientific' screen - tap the 'S' in the top right corner or use menu.
Scientific screen

Now you can easily write in '3*sin(pi/2)' and press 'Exe'. You can change between the screens, if you don't like graffiti. You can see somewhat shorter expression on the screen-shot - EasyCalc doesn't require closing brackets ('sin(pi+1' is interpreted as 'sin(pi+1)'), and supports shortened writing of multiplication - like '3pi' or '6e'. The priority of the hidden multiplication operator is very high, that's why you can easily write 3^6pi and 3^(6*pi) gets executed. The priority of an explicitly written multiplication operator is as expected. Before proceeding - try tapping the small black arrow to the right of the input field. What you see is history list, currently holding 15 last executed expressions. You may wonder, what is the Ans button for? It's for the last computed result. And the ans variable gets inserted automatically whenever you are on the beginning of the line and press some 'operation' button. Try writing sin(pi) and press Exe. Now tap a button +. On the screen appears ans+. Now if you complete the expression (e.g. with 1) end press Exe, you have effectively computed sin(pi)+1.

Now to some of the things you can see on screen. The 'Rcl' is for fast access to variables, 'F' is for fast access to functions and 'H' stands for history.

Trigonometric calculations

There are some comfort functions for working with degrees and radians. They are located in a small menu, that appears when you click the 'M' on the right side of the results field. It features - among others - the '->Degree' and '->Radian' function, that changes the output to a more readable form. Of course you can try the 'Copy' option and Paste it into the input field - and it works. The degrees are written somewhat easier this way: Degree notation

. Of course only if you learn, how to write the degree special character. The Degree/Radian/Grad can be switched in Preferences.

Preferences

Radian/Degree/Grad mode change - this change applies to all functions.
Decimal/Binary/Octal/Hexadecimal - this setting applies to output formatting
Integer input recognition and displaying functions, but doesn't change computing behavior. This means, that expression '3.14159' isn't recognized in non-floating modes, because '3.141..' is floating point number, while 'pi' outputs correct result regardless of mode, because 'pi' is a floating point constant. Generally you do not want to turn this option on, unless you want to work with base conversions, because floating point output formatting prints at most 10 digits, but the integer number formatting will print always the whole number (this makes sense only for 32-bit numbers converted to Binary).
Strip zeros - output '3.100' or '3.1'
Match ()'s - if on, then tapping on the function button automatically inserts closing bracket and moves cursor position between the brackets
Force complex nums - because complex operations are slow and usually less precise, all computation are done as 'real' by default. This doesn't confine you in the real sphere at all, because the calculator automatically switches to complex operations whenever it encounters complex numbers, but doesn't do them by default. If this is off, then sqrt(-2) will give you an error, but sqrt(-2+0j) gives a complex result - because of the automatic fall-back to complex numbers. When this switch is on, sqrt(-2) will be automatically return complex result.
Reduce precision - personally I don't like things like sin(pi)=1E-15. This is unfortunately the way most computers work and I can't do much about it, it is the limitation of floating point. If this is checked, EasyCalc displays numbers smaller then 1E-15 as zero (but you can still preform calculations with them). If you uncheck this option, you can see numbers up to 1E-100.
Show units - If checked and the engineer mode is selected, numbers get appended a unit to them at the output (e.g. 1E6 -> 1M ).

Integer calculations

Tap the 'I' on the top and change to the 'Integer' screen:
Integer screen

EasyCalc works with 32-bit unsigned integers and supports simple binary operations - AND(&), OR(|), ShiftLeft(<) and ShiftRitght(>). It also supports base conversions. If you do not check the Integer input in preferences, all numbers will be treated as 'float' and for float numbers are not defined the and,or,shl and shr operations. Write in some number and press the 'Exe' key and the number will appear in the Result area. Now tap on the base you want to convert to and the number will reconvert. If you convert from 'Float' to some integer base, the number gets rounded. DO NOT FORGET TO CHECK THE MODE BACK TO DECIMAL AND UNCHECK THE INTEGER INPUT, you can be surprised to see BAD results if you do not (3/2 in integer is not the same as 3/2 in floating point). BTW: If the result is longer than the result field, a small arrow appears on the right and you can scroll the field by touching the field and moving with the pen left/right.

Complex calculations

EasyCalc supports all ordinary computations with complex numbers (please, write me if you find some operation EasyCalc doesn't support, it is possible I forgot some of them). The 'i' works exactly as expected. On the second figure you see the result of number conversion in the 'M' menu.

Variables and functions

EasyCalc supports unlimited number of variables and functions. Variable (or function) name consists of lower-case letters and can be up to 10 characters long. Variables and functions share the same address space, so if you define a variable with same name as function, the function will be overwritten. Variable is defined simply by executing 'name=value', function is defined by executing 'name()="code"'. The 'name' cannot be 'pi', 'e' and 'x' as those are reserved identifiers. And now some examples: writing a=31 and tapping the Exe key will assign a number 31 into variable a. From now you can treat the a variable like other constants. If you now write a=3*a, variable a will contain a number 93.
Let's try to define a simple function now: write f()="x^2" and press Exe. From now you can use this a function - f(3) will return a result of 9. You can easily delete/modify all defined functions and variables by tapping the 'DataMgr' in the 'M'-menu on the right of the result field.

Financial calculator

Introduction to financial calculations

Basic financial calculation can be characterized this way: You have some money in the bank (PV, present value). X-times a year(P/YR, payments per year) you deposit some money (PMT, payment) into you bank account. Every year the bank adds some amount of money, it's a percentage of the amount that is currently on your account and the percentage is called interest (IT). After a given number of years (NP, Number of Payments) you decide to withdraw your money from bank. What you will get from bank is a future value(FV).

Financial screen

This is a basic implementation of financial calculator. You work with 6 different variables:
IT - interest pr. year. Note: from the 1.01 version this should be a per-cent number, e.g. 12% interest should be written as i=12 and not as i=0.12, like in earlier versions.
NP - number of payment-periods
PV - present value
PMT - payment (annuity) every period
FV - future value
P/YR - payments per year
and the Begin/End buttons, that affect when is the payment done - in the beginning of the year or at the end (usually at the end).
Now you can try defining 5 variables and by tapping on the name of the 6th it gets computed. Let's try an example:
By tapping on the buttons 'Undefined' near names of corresponding variables you can enter values for every variable. Now most of those 'Undefined' messages should have disappeared. If you tap on the name of the variable you wanted to compute, a notice 'Please wait' will appear in the middle of the screen indicating, that the calculator is computing, and you'll be able to read the result as soon as the sign disappears.

Graphs

EasyCalc can display functions on graph.It currently supports normal function graphs, polar and parametric graphs.

Let's begin with drawing a simple graph. Go to graph preferences (tap 'G' and then the letter 'P' or 'menu->Graph->preferences') and set it exactly as you can see it on the screen-shot.
Graph function
Now exit the preferences and go to setup (tap 'S' or 'menu->Graph->Setup funcs'). Tap the blank space on the right of 'Y1' and enter "x^2-4". Exit setup and look at the graph.
If you want to delete a function or graph an already existing one, tap on the function identifier (Y1,r1...) and a popup menu appears. Select 'None' to hide a function, 'User' to create a special function for this graph (the same one, as when you tap to the right of the identifier) or choose an already existing function.
Graph: x^2-4
What can you do with the graph screen? If you tap on the graph and move the pen, the graph moves too. After you lift the pen, the graph redraws. The '-' button is for 'zoom out' and the '+' button is for 'zoom in' (press the '+' button and draw a rectangle, where do you want the new screen to be).

If you want to read the graph values, go to Menu->graph->table mode, and what you read are values of the parameter (x) and values of f(x).

Graph Table mode
You may want to trace a function like in the older version of EasyCalc. Tap the 'T' on the right, select a function and tap on the screen. This works perfectly for normal functions, but works somewhat worse for Polar and doesn't work at all for Parametric functions. That's why you can use up/down arrows and/or the 'Go' button to draw a cross directly on some value.
Graph Trace Color Graph

Hints

If you have selected text on screen and tap a function button (e.g. sin, but a plain '(' would do), the selected text will be inserted into the function.
Remember that you can still use the on-screen keyboard anytime you need to input numbers. This is very handy in the 'GoTo' dialog when you are tracing function.
You may experience strange results when graphing functions do not have some values defined, e.g. tan(x) when you zoom-out. There is no way I can fix it if I do not want to make it considerably slower. You can make it slower yourself, when you draw this as a parametric graph (set 'X=x' and 'Y=tan(x)'. Then you can choose the T-step small enough to let the graph draw exactly as you expected..

Other functions

EasyCalc can guess a number - suppose you just computed 'acos(0)' and you don't know, what the result means. Use the M->GuessIt and it will tell you, that you just got 'pi/2'.

There are some undocumented functions:

% - modulo operator
' xor ' (space,'xor',space) or the 'yen' character - xor
fact() - computes factorial
ipart() - the whole part of a number
fpart(x) - x-ipart(x)
ncr(),npr() - combinations and permutations, these functions accept 2 parameters, e.g. ncr(3:1)
fzero - compute a 'zero' of a function in a given interval. This function takes 3 parameters - minimum, maximum, function. E.g: fzero(0:4:f()), where f()="x^2-4" will return '2' as a result. You can write it shorthand as fzero(0:4:"x^2-4").
EasyCalc with special functions supports these functions: gamma(z), beta(z:w), igamma(a:x), erf(x), erfc(x), ibeta(a:b:x), besselj(n:x), bessely(n:x), besseli(n:x), besselk(n:x), elli1(m:phi), elli2(m:phi), ellc1(m), ellc2(m), sn(m:u), cn(m:u), dn(m:u). If you want additional help, please look in specfuncs.tex that is included with the installation.

Contact, Newest information etc.

It might be useful to read documents you get with EasyCalc, especially 'INSTALL'.

EasyCalc was written by Ondrej Palkovsky, ondrap@penguin.cz. Latest information is available on http://easycalc.sourceforge.net. I send many thanks to people who reported bugs and sent me language corrections to this tutorial. This product is still changing and if you feel that you encountered a bug (including an error in this tutorial, english is not my mother language), please send me a note, I'll be happy to fix it.