The Alcula' Online Scientific Calculator (from now: "Calculator") is a virtual calculator application. It will continue to be extended with new functionalities to be defined in the months to come. Currently it support addition, subtraction, multiplication and division plus basic memory operation and parenthesis. More details of new functions as they are added, will be available on these pages.

The Calculator was developed for Flash player. To use the calculator, your web browser must support Flash and have a recent version of the Flash player installed. If it doesn't, or if the Flash version installed is too old to run the calculator, a message will appear the first time you access the calculator page, prompting you to install the player. Just follow the instructions and reload the page if necessary, after you have installed the player.

To use the calculator, goto the Calculator page. It is a fairly large file, and it will get larger as new functionality is added. Be patient and don't hit refresh if the calculator doesn't load straight away. After the calculator has been loaded the first time, the page will load faster.

**Note: These instructions refer to the old scientific calculator. To see the instructions for the new scientific calculator click here**

If your browser allows it, the contents of memory and displays are saved in your computer for next time you access the calculator, even if you close your browser or switch off your computer. This function only works when leaving the application 'cleanly'. If the browser is forced to terminate or the computer crashes, the content of the permanent memory will revert to what was saved in the previous session.

The Calculator supports the following operations:

- Addition (key '+')
- Subtraction (key '-')
- Multiplication (key 'X')
- Division (key '/')
- Power (key 'Xy')
- Change sign (key '+/-')
- Trigonometric functions
- PI

Parenthesis can be used to alter the order of operations. See Operator precedence for more information.

The calculator has one quick access memory that can be used for storing values temporarily. To clear the memory (set it's value to 0), press the key 'MC'. To recall the value stored in memory use the key 'MR'. To add to the value in memory, press 'M+'. To subtract a value from the memory use the key 'M-'.

Ten additional memories can be accessed using the 'STO' and 'RCL' buttons. To store the value currently displayed, press the 'STO' key. A message will appear ('Store (0-9):') requesting to enter the number of the register to store the value. Enter a number between 0 and 9. To recall a value from memory, press the 'RCL' key. At the message ('Recall (0-9):') enter the number of the register you want to retrieve.

As you enter a value, the digits you type appear on the 'main display'. When you enter an operator (ex. '+') the number you typed moves to the top display, followed by the operator you just typed. The main display only holds the last typed value or the result of the last operation.

The Expression Display is updated every time you type a parenthesis, an operator key or the '=' key to calculate the result.

The 'C' (Cancel) key has dual functionality depending on when it his used:

- If it is pressed while typing a number, the last figure typed is deleted.
- If the 'C' key is pressed after an operator or the = sign. The full last value entered is deleted from the expression display. This is useful because it allows to retroactively modify the parameters of a calculation after the calculation has been made.

The 'AC' (All Cancel) key deletes the content of the main display and the content of the expression display but it does not erase the content of the memory.

The '+/-' changes the sign of the value currently displayed. For example: the result of the last calculation displayed on the main display is 5. After you hit the '+/-' key, the display changes to -5 . You can then use this result as starting value for your next calculation.

The 'Xy' key can be used for calculating the power: enter the number to be raised to a power, followd by the 'Xy' key, followed by the power.

These keys are used for trigonometric functions. The angle must be entered in radians

The PI key retrieves the approximated value of PI: 3.14159265358979

These keys are used to calculate the natural logarithm, common logarithm and respective antilogarithms.

To calculate the number of permutations (without repetition) of size r from a set of size n:

- Press the 'P(n,r)' key
- Enter the value n
- Press the ',' key
- Enter the value of r
- Close the parenthesis by pressing the key ')'
- Press '=' if you want to calculate the value immediately or continue typing the expression.

This key is used to calculate the number of k-combinations from a set of n elements. Use the ',' key to separate the two parameters:

- Press the 'C(n,k)' key
- Enter the value n
- Press the ',' key
- Enter the value of k
- Close the parenthesis by pressing the key ')'
- Press '=' if you want to calculate the value immediately or continue typing the expression.

This is the factorial key. It's different from the other functions of the calculator in that the '!' symbol is appended to the end of the number. For example to calculate the factorial of 6:

- First Enter the number (6)
- Press the factorial key
- Press '=' if you want to calculate the value immediately or continue typing the expression.

The square root function. Press the key first followed by the value for which you want to calculate the square root.

This key is used to separate the parameters when entering functions. See the description of P(n,r) and C(n,r) for instructions on how to use this key.

Using the computer keyboard is possible after clicking on the calculator once. Click here for more information on using the keyboard.