# Vinny RPN Calculator 2022-1

INTRODUCTION
Vinny RPN Calculator 2022-1 is a FREE app for science and engineering students. It uses Reverse Polish Notation. It temporarily converts the computer's numeric keys into an RPN calculator. It allows direct use of the computer numeric keys and math keys [ +,-,*,/ ]. The values can be input in decimal or exponential format. The main menu item [Hide Trig] Shows & Hides the Trig & Log functions. The mouse activates them. In order to facilitate [Copy] and [Paste] to other apps, Vinny RPN stays on TOP and is therefore always visible. The [Help] menu item toggles the help window between open and close.

T: [T] register (top) display only.
Z: [Z] register display only.
Y: [Y] register display only.
X: [X] register working register.

CALCULATOR OPERATION
The app [Enter] button or the computer [Enter] key is one of the ways to complete [X] register data entry but it is not always required. When used it will duplicate the [X] value into the [Y] register and RAISE the the stack one notch. Note the value in the [T] register is lost.

Trig, Log, Power and Root functions operate just on the [X] register and do not affect the stack. These functions will complete [X] data entry.

Dual functions use both [X] & [Y] register in their calculations. These include [+,-,*,/], [Y^X] and [Delta %]. Each dual function will LOWER the stack one notch and duplicate the [T] value in the [Z] register. The calculation result is displayed in the [X] register.

COMPUTER KEYS
Number keys enter numerical digits. Keyboard functions [+,-,*,/] do simple math on [X] & [Y] values.

[Enter] key duplicates [X] value in [Y] & raises the stack one notch. [Up/Down] cursor keys rolls the stack up or down one notch.

[PageUp] key toggles exponential format and the +/- sign of the exponent. [PageDown] key toggles the +/- sign of the exponential mantissa.

[Home] key reformats the "X" display's decimal point location and exponent. [End] key interchanges the [X] and [Y] register values.

DATA MOVEMENT
The [X<>Y] button and the computer [Home] key both interchange the values in the [X] and [Y] registers. The down roll [R] button rolls the [X,Y,Z,T] stack down on notch. The computer [Up or Down] cursor keys respectively roll the stack up or down one notch.

DATA FORMAT
The main menu item [Set Decimal] opens a dialog box for setting the number of digits displayed after the decimal point. To activate the setting and to close the dialog box use the Computer [Enter] key or just click on the [Set Decimal] menu item again. Use [PgUp] key or [E+/-] button to enter exponential format and to change exponent sign.

RPN FUNCTIONS
[1/X],[Y^x]
[sqr(X)], [X^2]
[sin], [cos], [tan]
[asin], [acos], [atan]
[log], [10^x]
[ln], [e^x]
[Trig] & [Log] Buttons act on [X] register value.
Click the red [Degrees/Radians] label to switch Trig units.
Delta % between [X] and [Y] { X = 100% * (X-Y)/Y }.