## Welcome to the## RootM™ 1.2## Complex-valued RPN Calculator## Documentation |

IMPORTANT: If you do not see any images and are running Windows XP you need to extract the files from the .zip archive before viewing. Open the .zip file and select "Extract All Files". ## Contents

- What is RootM?
- What is new in Version 1.2?
- System Requirements
- Installation
- Registration
- Reverse Polish Notation
- Entering Complex Numbers
- Accessing Functions
- Complex vs. Real Functions
- Walkthrough
- The Display
- Menus
- Preferences
- Basic Functions
- Keyboard and Treo support
- 5-way button support
- International Number Formats
- Stack and Register Functions
- Scientific Functions
- Trigonometric Functions
- Time Functions
- Polar Coordinates
- Number Base Functions
- Modular Functions
- Financial Functions
- Statistical Functions
- Legal Stuff
- Contacting Creative Creek™
## What is RootM?

RootM is an RPN scientific calculator for the Palm OS that natively support computations containing imaginary numbers. This means that sqrt(-1) or asin(2) are valid computations, producing complex results. Complex numbers can be entered in real/imag format or mag/phase format in a straightforward way. Quickly switch between real/imag and phasor (mag/phase) displays. RootM has a 16 high stack and 20 memory registers -- all of which can store complex results.

RootM is a advanced scientific and financial calculator too. RootM has functions to compute loan and mortgage terms and well as simple statistics. The keyboard is packed with functions and more are available via the pop-up menu. In total, RootM has 85 scientific, financial, statistical, and number base functions.

Technical specifications

- Easy complex number input
- Personalizable keyboard skins
- Two line stack display
- Supports color, grayscale, and B&W devices.
- Pop-up list of all the built-in functions on main keyboard
- Double precision accuracy (about 16 decimal digits)
- Full IEEE range 2.2e-308 to 1.7e+308
- 16 element stack
- 85 built-in functions (including 36 complex valued functions, 5 financial functions and 8 statistical functions)
- Hex, oct, and bin conversions
- 20 memory registers
## What is new in Version 1.2?

Version 1.2 adds:

- Palm Security app
compatibility.5-way navigatorsupport.Treo specific features.Beamabletrial.Version 1.1 added:

Optimized for Palm OS 5.0 and the Sony CLIE.New high resolution keypad!## System Requirements

RootM requires Palm OS 3.0 or higher and 212K of RAM.

RootM works on any handheld device that is running Palm OS 3.0 or higher including all devices from Palm, Inc. (Zire, Tungsten, Treo, and LifeDrive) as well as the Handspring Visors, the Sony CLIE, the HandEra, and the IBM Workpad. RootM has been enhanced to take advantage of the high resolution screens.

## Installation

To install RootM simply unzip the archive you downloaded and use the install tool (or equivalent) to install

RootM.prcon your Palm device. You might also consider assigning the calculator button to bring up RootM instead of the default calculator after syncing. To do this, go to the Prefs application, select Personal, and then Buttons. Select RootM from the list next to the button you wish to reassign.To uninstall RootM, simply delete RootM via the Palm applications screen.

## Registration

RootM features a free 15 day trial. All the features of RootM are available during the trial. The only difference between the trial and a registered version is that the registration screen no longer displays on startup. After the 15 day trial, the five key (5) becomes disabled. If you decide that you like RootM, purchase a registration code to unlock it.

A registration code can be obtained by purchasing RootM from Creative Creek, LLC. You must provide the user name shown in the registration screen to obtain a valid code. The code will be emailed to you a few days after registration.

To register your software, select the Display->Registration menu item to bring up the registration screen.

Use graffiti (or the popup keyboard) to enter the registration code you received in the mail into the field following "Reg. code:" and tap OK. If the code you typed in is accepted, the screen will disappear and the RootM keyboard will be displayed. If you make a mistake in entering in the code, a dialog will indicate that the code wasn't valid and you will be given a chance to edit the code. If you wish to dismiss this dialog without entering a registration code, simply remove all the characters from the Reg. code field and tap OK.

If for any reason you have trouble registering your software please contact us via the Contact Page for assistance.

## Reverse Polish Notation

RootM is a reverse polish notation (RPN) calculator. Numbers are entered onto the stack. Functions take their inputs from the stack and push their results onto the stack. The notation takes some getting used to but it is worth learning. Among its many benefits is an increased confidence in the results since all the intermediate calculations are displayed immediately. How many times you have you had to double- and triple-check a calculation when using an algebraic calculator?

As a simple example, the formula 14 * sin(60) is solved using RootM like this

button display [1] 1 [4] 14 [ENTER] 14. [6] 6 [0] 60 [f] [SIN] 0.866025404 [x] 12.124355653The [ENTER] key is used to separate the numbers during input. Alternatively, you can avoid using the [ENTER] key by evaluating the expression "from the inside out"

30 [f] [SIN] 10 [x]This approach of evaluating from the inside out can be used to evaluate complicated expressions with the same level of confidence in the answer. For example, the equation

x = (-b + sqrt(b

^{2}- 4*a*c))/(2*a)is used to compute the roots of the quadratic equation (a*x

^{2 }+ b*x + c=0). Suppose a=2, b=0.5, and c=1.2, then the steps to solve this using RootM are (working from the inside out).0.5 [f] [X^2] 4 [ENTER] 2 [x] 1.2 [x] [-] [SQRT] 0.5 [-] 2 [ENTER] 2 [x] [÷] ans: -0.125 +i 0.764444243(where [SQRT] is the square root key, [÷] is the divide key and [x] is the multiply key). The result is complex since the input to [SQRT] is negative. Check the result by plugging the solution into the original equation:

[STO] 0 [f] [X^2] 2 [x] 0.5 [RCL] 0 [x] [+] 1.2 [+]As expected, the equation evaluates to zero.

## Entering Complex Numbers

To enter complex numbers in real/imag notation, use the [+i] key between the real and imaginary parts. For instance, to enter the complex number 2 + i 5 into RootM tap

[2] [+i] [5]To enter a complex number with a negative real or imaginary part (e.g. -2 -i 5) use the CHS key

[2] CHS [+i] [5] CHSTo enter complex numbers in magnitude/phase notation, use the [/_] (g ENTER) key between the magnitude and phase parts. For instance, to enter the complex number (phasor) 15 @ 30 degrees tap

[1] [5] [g] [/_] [3] [0]When you first start RootM, complex numbers are displayed in real/imag format. To display them in mag/phase format tap R->P key. Tap P->R to return to the real/imag format. You can also change the complex number display format in the references screen (choose RECT or POLAR). If you prefer to use +j for the imaginary unit, there is a preference to change it.

## Accessing Functions

Most buttons on RootM can access three functions. The function or number in the middle of each button is accessed without shifts. The function just above the button is accessed by pressing the f-shift key [f] before pressing the button. The f-shift indicator will light in the display when the f-shift is active. Similarly to access the functions on the front of the buttons use the g-shift key [g]. The g-shift indicator will light in the display when the g-shift is active.

Most functions remember the last x register value used during a computation. This value can be accessed via the [lastx] function. RootM has a 16 element stack. The first four elements of this stack are referred to by the names x,y,z, and t.

The value of the x register is what is displayed. When the "Show more stack values" preference is checked, the y register will also be displayed.

## Complex vs. Real functions

## Complex functions

Many, but not all, of the functions built into RootM support complex number inputs. Here are the functions that do:

## Arithmetic functions

[+] [-] [x] [÷]These functions operate on the values in the x and y stack registers, and produce complex results.

## Scientific functions

[SIN] [COS] [TAN] [SIN^{-1}] [COS^{-1}] [TAN^{-1}] [SINH] [COSH] [TANH] [SINH^{-1}] [COSH^{-1}] [TANH^{-1}] [LN] [LOG] [EXP] [10^{x}] [X^{2}] [SQRT] [Y^{x}] [1/x]These functions operate on the x register and replace it with the complex result.

By default, these functions treat any inputs outside the normal real domain as if they are in radians even when the angle preference is degrees or grads. For example

30 [SIN]produces

0.500when in degrees since the input is within the real domain of [SIN] while30 [+i] 0.00001 [SIN]produces

-0.988 +i 1.543e-6(which is the radian result) since the input is outside the real domain of [SIN].If you would rather have the scientific functions error for inputs outside the real domain when the angle preference is not radians, check the "Require radians for complex funs" on the "More preferences" screen. In this case, the second example would have produced an error. You would have to switch the calculator to radians to get the above result.

## Complex conversion functions

[C->R] Complex to real conversion. Breaks the value in the x register into real and imaginary parts.

[R->C] Real to complex conversion. Uses the real parts of the values in the x and y registers to construct a complex number.

[CONJ] Complex conjugate. Replaces the value in the x register with its complex conjugate.

[ABS] Absolute value or magnitude. Replaces the complex value in the x register with its magnitude. For real inputs, this amounts to stripping off the sign.

[ARG] Complex argument or phase angle. Replaces the complex value in the x register with its phase angle expressed in the current angle units (degrees, radians, or grads).

[R->P] When either x or y has a nonzero imaginary part, R->P changes the complex display mode to POLAR so that complex numbers on the stack are viewed in magnitude/phase format. The values on the stack are unchanged. When both x and y are real, R->P converts them from rectangular coordinates to polar coordinates.

{P->R] When either x or y has a nonzero imaginary part, P->R changes the complex display mode to RECT so that complex numbers on the stack are viewed in real/imag format. The values on the stack are unchanged. When both x and y are real, R->P converts them from polar coordinates to rectangular coordinates.

[+i] or [+j] start imaginary part

[/_] start angle part

## Real functions

The remaining functions built-in to RootM only support real inputs -- they produce an error when presented with a complex value (i.e. a value with a nonzero imaginary part). Use [ARG], [ABS], or [C->R] to convert complex numbers into real numbers suitable for the real-valued functions. These functions are

## Financial functions

[N] [i] [PV] [PMT] [FV] [CLFIN]

## Statistical functions

[S+] [S-] [MEAN] [STD] [N!] [%] [%CH]

## Number base functions

[HEX] [OCT] [BIN] [AND] [OR]

## Time functions

[->H.MS] [->HRS]

## Other functions

[PI] [SECONDS] [RAND] [->DEG] [->RAD] [INT] [FRAC] [MOD]

## Walkthrough

## RootM Walkthrough

(A guide to the RootM interface)

## The display

The display can show numbers in several formats depending on the preferences you have chosen. Numbers can be displayed in

- fixed or scientific formats (FIX, SCI, ENG preference). The three screens below show the number 12345.6789 in the three formats

FIX format SCI format ENG format - with 0-9 or all significant digits (0-9 or All digits preference).
- in alternative number bases (HEX,OCT,DEC,BIN preference). The four screens below show the number 1234 in the four formats

HEX OCT DEC BIN - In addition complex numbers can be displayed in real/imag format or Mag/phase format (RECT, POLAR preference). The two screens below show the complex number 3+i 4 in the two formats

RECT POLAR

The last screen shows that 3 +i 4 can be represented in polar format as 5 /_ 53.13 degrees.- Finally, the display can use a large font that is easy to read or a smaller font so that both the x and y registers can be displayed at once ("Show more stack values" preference)

Show more stack values unchecked Show more stack values checked - When All digits and "Show more stack values" are both selected, RootM will attempt to show up to 16 significant digits if the number will fit on the display.
Tap the display to bring up the quick stack list. This selecting an item in the list, will push it into the x register.

## Menus

(main screen)

Copy: Copy the current value of the x stack register to the clipboard. Complex values copied when shown in mag/phase (POLAR) format use the @ character in place of the /_ (angle) character.Paste: Interpret the text on the clipboard as a number and push it onto the stack as the x register value.(main screen)

Registers: Display the Registers and stack screen.Help: Display the built-in help screen.Preferences: Display the preferences screen.Registration: Display the registration screen.About RootM: Display information about RootM.## Preferences

The preference screen is displayed when you choose Display->Preferences from the menu or when you tap the angle indicator on the screen (see walkthrough above).

Skin:Choose your desired color scheme from the list. Lists all available skins.Format:RootM can display results in either fixed, scientific, or engineering format.Fixed formatdisplays results with a fixed number of decimal digits but will over- or underflow to scientific notation if the value is too big or too small.Scientific formatdisplays all results in scientific notation with a fixed number of decimal digits. Numbers in scientific notation are displayed as

which is interpreted as the number 1.234567890 x 10^{99}.Engineering formatis just like scientific format except that the exponent is always a multiple of three.Digits:Number of digits or All if you want all the significant digits to displayed. The number of digits displayed depends on the format. In scientific and fixed format, it is the number of digits after the decimal. In engineering format one more than the number chosen significant digits are displayed. When the "Show more stack values" preference is checked (see below), RootM will attempt to show up to 16 digits of precision when All is selected and the number would fit in the display.Angles:Angle domain for trigonometric functions. The state of this preference is also indicated in the display.Payment:Financial annuity mode. Payments can be due at the beginning of the pay period (annuity due) or at the end of the period (ordinary annuity). The state of this preference is also indicated in the display.Complex:Complex number display format. Chose RECT to display complex numbers as real/imag parts or POLAR to display complex numbers in Mag/Phase notation. This preference has no effect on the display of real numbers.Binary bits:Number of bits to use for integer base functions like Hex, Oct, and Bin. Values larger than this number of bits will continue to be displayed. Execute an integer base function to truncate such integers to bring them into range.Press OK to commit your changes. Press Cancel to leave them as they were. The More button brings up an additional preference screen.

Imaginary Unit:Choose +i or +j as the imaginary unit (sqrt(-1)).- Require radians for complex funs: When checked, RootM generates an error if the inputs to trigonometric functions are outside the normal real domain. Otherwise, inputs outside the normal real domain are treated as radians even when the angle mode is degrees or grads.
Quiet buttons:When selected, button presses will no longer click when pressed. The sound from errors, alarms, or from other applications are unaffected.Emulate 4 element stack.When selected, all stack operations from the keyboard act as if the stack only had 4 elements. Programs can still access all 16 registers of the stack even when this is selected.Show more stack values.When selected, RootM tries to show as many stack values as will fit in the display.Pressing Close on this dialog will not affect your current preferences until you press OK on the previous dialog.

## Basic Functions

[7] [8] [9] [4] [5] [6] [1] [2] [3] [0] [.] Numerals [A] - [F] Hexadecimal digits (only valid when number base is HEX) [CHS] Change sign of mantissa or exponent. [CONJ] Complex conjugate (change sign of imaginary part) [EEX] Start entering exponent [<--] Undo last character (or clear x register) [-] Minus. [+] Plus [x] Times [÷] Divide [ENTER] Separate values and prepare x register to be overwritten [+i] or [+j] Start entering imaginary part [/_] Start entering phase part R->C Convert from real/imag to complex C->R Convert from complex to real/imag R->P Display complex values in POLAR notation When both X and Y are real, [R->P] converts (x,y) into polar coordinates (R,theta). When either is complex, just changes the complex display preference. P->R Display complex values in RECT notation When both X and Y are real, [P->R] converts (R,theta) into Cartesian coordinates (x,y). When either is complex, just changes the complex display preference.

Keyboard and Treo SupportRootM allows you to input numbers using Graffiti. The characters 0 through 9, decimal, minus sign, 'e' and the graffiti return character can be used instead of the numeric buttons, [.], [chs], [eex], and [enter]. In hexadecimal mode, you must use Graffiti or the keyboard to enter the letters A through F. The characters '+', '-', '*', '/' can be used instead of [+], [-], [x], or [÷].

On the Treo, the keyboard is automatically option-locked into numeric mode. Letters like 'e' that share space with the numbers can be accessed by pressing option before pressing the key. After each press, the keyboard will automatically return to numeric mode. Pressing the center of the 5-way is the same as [enter].

When in hex mode, the keyboard is automatically locked into alpha mode in order to make entering A-F easier. To enter numbers, press option before each number or use the MathU Pro keypad.

On devices with the 5-Way navigation button, the 5-way can be used to highlight and select the buttons on the keypad. When no buttons are highlighted, the 5-way up and down scrolls the stack.

## International Number Formats

RootM honors the number format chosen in the system Prefs application. If you find that RootM is displaying numbers using the wrong decimal or thousands separator, go to the system Prefs application and choose Formats from the popup menu. Choose the number format for your locale from the

Numbers:popup.For number formats that use the comma as the decimal separator, RootM displays [,] instead of [.] for the decimal button. Changing the number format affects the way values are displayed, copied, and interpreted during a paste.

## Stack and Register Functions

RootM has a 16 high stack that persistently stores the results from previous computations or numbers that have been pushed onto it via [ENTER]. The stack can be cleared with the [CLSTK] function, the x register is cleared with the [CLX] function or [<--].

To quickly access a previous result or to just view the stack, tap on the display to bring up the stack view.

When you tap an element in this list, it will be pushed onto the stack and the list will disappear. To make the list disappear without changing the stack, tap OK.

RootM has 20 registers -- 10 primary registers and 10 secondary registers. The secondary registers are used to store values for the financial and statistical functions. The secondary registers can be used to store your own values but you must be careful not to use any financial or statistical functions if you do so.

The 10 primary registers are accessed by pressing [STO] or [RCL] and then the register number [0] through [9]. To access the secondary registers (registers 10 through 19) press [STO] [.] and then the register number [0] through [9]. Another way to access the secondary registers is to swap the primary and secondary registers with [p<>s] and then use [STO] or [RCL] (without the [.]).

The registers and stack can be viewed by choosing Display->Registers from the menu or by tapping the [RCL] key twice.

Choose OK to return to RootM. Tap on Register or Stack to see the values. Tap Hex, Dec, Oct, or Bin to view integer values stored in the registers in the chosen number base. Select an element in the list to push it onto the stack.

## Scientific Functions

The unary functions operate on the value in the x register and replace it with the function result (f(x))

while the binary functions use the values in both the x and y registers and place the result in the x register.

KeyFunctionDescriptionTypeDomain [f] f shift. Use to access functions above each button. [g] g shift. Use to access the functions at bottom of each button. [ABS] abs Absolute value (complex magnitude) unary complex [ARG] arg Complex argument (phase angle) unary complex cbrt Cube root unary complex chop Round value to display precision unary complex mod Modulo (y - x * floor(y/x)) binary real [Pi] pi Value of pi unary real [LN] ln Natural logarithm (base e) unary complex ln1p ln(1 + x) more accurate for x near zero unary complex [LOG] log Base 10 logarithm unary complex [e ^{x}]exp Exponential function unary complex expm1 exp(x) - 1 more accurate for x near zero unary complex [10 ^{x}]pow10 Ten to the x power unary complex [y ^{x}]ytox y to the power of x binary complex [x ^{2}]sq Square unary complex [SQRT] sqrt Square root unary complex [1/x] inv Reciprocal unary complex [FRAC] frac Fractional part unary real [INT] int Integer part unary real floor largest integer smaller than or equal to x unary real ceil smallest integer larger than or equal to x unary real fact Factorial unary real [%] % Percent (y * x) / 100 binary real [%ch] % ch Percent change 100 * (x - y) / y binary real The

`int`

and`frac`

functions round to 9 decimal digits before determining the integer and fractional parts. Under this definition`frac`

is computed using the formulafrac(x) = x - int(x)Most of the time this produces the desired results but does treat the input as if it only had 10 digits of accuracy. One of the ramifications of this is that the fractional part doesn't always have the same sign as x. Take for example the number 1.99999999964 (i.e. 2 - 36e-11). When displayed in RootM this number looks like it is 2.0. Because of the rounding int(x) is 2 (as expected) while frac(x) is -36e-10.

The ceil, round, and floor functions do not do this rounding and may be more appropriate to use if you need to take advantage of all 16 digits of accuracy that RootM maintains.

## Trigonometric Functions

The trigonometric functions are sensitive to the angle mode: degrees, radians, or grads (deg, rad, or grd in the display where 360 degrees = 2 pi radians = 400 grads).

- When in degree mode, real domain inputs to sin, cos, and tan are assumed to be in degrees and the results from sin
^{-1}, cos^{-1}, and tan^{-1}are in degrees.- When in radian mode, the inputs and outputs are assumed to be in radians.
- When in grads mode, the inputs and outputs are assumed to be in grads.
- When the preference "Require radians for complex funs" is checked, RootM generates a error if the inputs to the trigonometric functions are outside the normal real domain. Otherwise, inputs outside the normal real domain are treated as radians even when the angle mode is degrees or grads.
Set the angle mode using the Preferences dialog (available from the Display menu) or via the angle function. Except for atan2, these functions operate on the value in the x register and replace it with the function result (f(x)).

KeyFunctionDescriptionType[SIN] sin Sine unary [COS] cos Cosine unary [TAN] tan Tangent unary [COS ^{-1}]acos Arccosine unary [SIN ^{-1}]asin Arcsine unary [TAN ^{-1}]atan Arctangent unary atan2 Two argument arctangent: same as atan(y/x) but in the correct quadrant binary sinh Hyperbolic sine unary cosh Hyperbolic cosine unary tanh Hyperbolic tangent unary asinh Hyperbolic arcsine unary acosh Hyperbolic arccosine unary atanh Hyperbolic arctangent unary [Pi] pi Pushes the value of pi (3.14159...) onto the stack. [->DEG] deg Radians to degrees conversion unary [->RAD] rad Degrees to radians conversion unary ## Time Functions

RootM has three time functions

seconds:Pushes the current number of seconds since January 1, 1904 onto the stack.H.MS:Converts x stack value from fractional hours to H.MS format. In H.MS format, the integer part of the value is the number of hours while the fractional part is broken into two fields: M, the minutes, and S, the seconds. Each field comprises two digits of the fraction. For example, the number 2.03165 is interpreted as 2 hours, 3 minutes, 16.5 seconds or 2°3'16.5" using standard degrees, minutes, seconds notation. Thus, the H.MS interpretation is also valid for D.MS as well. When using the H.MS and hours functions is usually helpful to set the number of digits displayed to be 4 or greater.hours:Converts x stack value from H.MS format to fractional hours. Digits after the fourth fractional digit are interpreted as fractions of a second.## Polar Coordinates

RootM provides two functions to convert back and forth between Cartesian (rectangular) coordinates and polar coordinates. The relationship between polar coordinates and Cartesian coordinates is defined by the following picture and formula

x = R cos(theta)

y = R sin(theta)

R = sqrt(x^{2}+ y^{2})

theta = atan2(y,x)## Number Base Functions

RootM can display and compute with numbers in hexadecimal (base 16), octal (base 8), and binary (base 2) format as well as the default decimal (base 10) format. Non-decimal values are displayed with a subscript following them indicating the number base. The number base functions honor the wordsize set in the preference screen.

hexadecimal display octal display binary display The functions hex, oct, bin, and dec convert values between bases and set the number base for further calculations and input. Use any combination of the numeric buttons and Graffiti to input non-decimal numbers. You must use graffiti to input the hexadecimal characters A through F since no buttons exist on the calculator for them. They do exist as program steps however.

Values outside the wordsize preference are wrapped (that is, the excess most significant bits are dropped) and are converted to an integer. The display will automatically switch to a smaller font when large numbers are viewed in oct or bin format. Large binary numbers may wrap on the display as well.

## Modular Functions

A few functions behave differently when a non-decimal number base is chosen:

The other functions on the calculator can be applied to non-decimal numbers. However, if the result is not an integer that is in range, an error is displayed and the number base reverts to decimal. The value in the x register will be the result of the computation. Simply reapply the conversion routine to wrap and truncate the value to be in range.

## Financial Functions

The financial functions are governed by the equation,

PV*(1+i)

^{N}+ PMT/i*((1+i)^{N}-1) + FV = 0This equation is used when the annuity mode (BEGIN/END preference) is set to ordinary annuity (payments due at the end of the period [end]). When the annuity mode is annuity due (payments due at the beginning of the period [begin]) then PMT in this equation is modified to be PMT * (1 + i).

The financial functions have two modes:

input modeandcalculation mode. RootM is ininput modeif a number has been keyed into the calculator or any non-financial functions have been executed. Executing one of the main financial functions ([n], [i], [pmt], [pv], or [fv]) stores the displayed value in the associated financial register. RootM is incalculation modeafter any financial functions have been executed and before any other functions that change the stack are executed. The result of a financial computation is pushed onto the stack:Most of the time this should behave as you would expect. However, if for some reason RootM stores a value when you intended to compute one, simply execute the financial function again to obtain the desired result.

## Cash Flow Convention

Financial problems can be thought of as a series of cash flows. For example a mortgage consists of a large positive cash flow (the loan amount) followed by a series of monthly negative cash flows (the payments) with possibly a final negative cash flow at the end (the balloon payment). The diagram below illustrates this situation.

Positive cash flows (amounts you receive) are shown as upward pointing arrows. Negative cash flows (amounts you pay) are shown as downward pointing arrows. The horizontal axis of the diagram is time, with time increasing to the right. The time between the equally spaced payments is called the period.

For the problem to be solvable with RootM, there must be at least one cash flow in each direction. It is always possible to add a present value or future value cash flow to meet this requirement. Think about your problem to determine which is more appropriate (see example 4 below).

## Examples

Example 1:Suppose you are interested in determining the payment for a car loan of $18,500 at 7.25% interest for 5 years. The key strokes to solve this problem using RootM are

- [clfin] to reset the financial registers (since the values in the registers are maintained between sessions with RootM it is a good idea to reset the financial registers before each use of the financial functions).
- [5] [enter] [1] [2] [x] [n] to set the number of periods (in months)
- [7] [.] [2] [5] [enter] [1] [2] [÷] [i] since the interest per month is 7.25/12 %
- [1] [8] [5] [0] [0] [pv] to set the principal or present value of the loan
- [pmt] to compute the payment per period (ans: $-368.51). The value is negative because the payments are made in the opposite cash flow direction from the principle cash flow. [If it makes more sense to you for the payment to be positive, unselect the "Use cash flow convention" preference.]

Example 2: What is the payment if you are willing to pay a balloon payment of $2,000 at the end of the loan?

- [2] [0] [0] [0] [chs] [fv] Set the value $-2,000 as the FV (balloon) for the loan. The value is negative because this is money you will pay out.
- [pmt] to compute the new payment per period (ans: $-340.75)

Example 3:How much interest do you end up paying with the balloon payment?

- [n] [pmt] [x] [fv] [fv] [+] [pv] [pv] [+] to compute the total payments minus the loan value

(ans: $-3,945.17). Note that [fv] and [pv] had to be pressed twice since the first time stored the total payments into FV or PV.

Example 4:To compute the effective interest rate in an IRA account that you put $2000 into each year, you will need to enter the current value of the account as a positive future value (FV) even though you haven't sold the assets in the account. To make the example concrete, suppose that you started your IRA in 1985 with a $10,000 rollover and that the value in the account is $80,000 in the year 2001.

- [clfin] to reset the financial registers
- [2] [0] [0] [1] [enter] [1] [9] [8] [5] [-] [n] to set the number of periods (in years)
- [1] [0] [0] [0] [0] [chs] [pv] to set the starting value of the account. The value is negative since you added this value to the account with the rollover.
- [2] [0] [0] [0] [chs] [pmt] to set the annual contribution.
- [8] [0] [0] [0] [0] [fv] to set the current value of the account. The value is positive since this is the money you would receive if you sold all the assets in the account.
- [i] to compute the effective annual rate of return in the account (ans: 6.39%)
## Statistical Functions

The statistical functions accumulate sums based on the values in the x and y stack registers. These sums are used to compute the mean [mean] and standard deviation [std] or can be accessed directly via [p<>s] and [RCL]. Use [CL S] to reset all the statistical registers to zero before accumulating sums. If you make a mistake keying in the x,y values and after pressing [S+], re-key the errant values and press [S-] to remove them from the sums. The mean and standard deviation are computed as

with similar equations holding for the y component as well.

## Legal Stuff

Although care has been taken to insure a bug-free program, Creative Creek, LLC makes no warranty whatsoever, either implied or expressed, as to the correct functioning of this software. When using this software, the user assumes all responsibility for any damages caused, directly or indirectly, by its use.

RootM is copyrighted. Copyright laws apply and the software shall be classified as proprietary material. The unregistered version may be given to your friends. If you want to include RootM on your web site or to distribute it in any way, please contact us at our contact page.

When you purchase RootM you are granted a non-exclusive, non-transferable license to use the software and documentation for use in accordance with this License. This License allows use of the software by a single user unless otherwise specified by the description provided at time of purchase.

RootM and Creative Creek are trademarks of Creative Creek, LLC. Palm, Palm OS, and HotSync are trademarks of Palm, Inc. or its subsidiaries.

## Contacting Creative Creek

## Contacting Creative Creek

See the Creative Creek web site (www.creativecreek.com) for up-to-date information about RootM.

If you have questions, suggestions, bug reports, or you just want to tell us how you much you like RootM you can contact us on the web at http://www.creativecreek.com.

Copyright © 2001-2007 by Creative Creek and Clay M. Thompson -- All rights reserved.

Last updated: 10-May-2007