How to define my own functions?

1. Select menu: tools->options[Ctrl+P] to open options dialog, select the "Function" tab.

2. Right click in the function name list to the left of the dialog, and you should see the popup menu.

3. Select "New Function" and open a function info dialog. Fill the function name, parameters, formula, and description(optional) in the dialog.

4. Press "Add" to save it.

5. System will check if the new function is valid, and give you a message to help you fix the problems if it's not.

For more detail, please reference Options->Functions.