"Leopoldine" wrote:
How can VBA knows the scientific functions defined in Excel?
Is there a library to define all these functions in a VBA workbook?

If you would like to use an Excel spreadsheet function in VBA, use the
WorksheetFunction object.

WorksheetFunction.function(arg)

Note that not all worksheet functions are available this way. There's no
need to declare them or provide a reference, if that's what you were asking.
Or was there something else you wanted to do?