# TABULA/samples/pick function line

## How to use the Functions tab to create a new calculated line

You could in principle create any desired calculated line by creating it as a sum of the intended input quantities, and then editing its formula, replacing the summation with any desired formula. But this would need looking up a stored list of stock formulas and copying them into the line's formula by hand, or pasting in the formula and editing it to fetch its input quantities from existing ones in your t-table. Not a straightforward task.

TABULA offers you a far easier way. It keeps a collection of stock formulas as complete calculated lines which you import into your t-table as needed. This straightaway gives you a working line, which you stitch into your t-table using the merge tool.

The Functions tab shows a collection of **function lines**,
i.e. calculated lines too complicated to build conveniently one line at a time using the toolbar and main menu.

You choose a single line and **append** it to the t-table.
The result is to create

- a calculated line derived from the
**Functions**line you selected - one of more
**feeders**: "leaf" lines supplying input values to the calculated result.

You can incorporate a feeder line directly into your t-table by repositioning it, renaming it, and maybe changing its units to compatible units of your own choice, e.g. metres to feet

Alternatively you can merge each feeder with an existing line of your t-table…

- the units of the two lines must be compatible
- the resulting combined line replaces the uppermost line, retaining its position name, value and units. But it now functionally replaces the feeder line, as the redrawn arrow shows.

[SHOW EXAMPLE HERE]

Therefore you should position the feeder line *below* the existing line it is to be merged with.
If you don't delay merging all the feeders after creating your new function line, you never need to rearrange lines beforehand, because the new calculated line plus its feeders are always created at the *bottom* of the t-table, and are thus in the correct position already.

## To pick a function line from the Functions tab

To pick a function line

- click the Functions tab
- browse the table of function lines
- type a
*filter*string to narrow down your search - click on your chosen line to select it
- press the button:
**Append**.

Instead of the last two steps, you can doubleclick your chosen line.

As a result, two or more lines appear at the bottom of your t-table: a new calculated line and its feeder line(s).

[SHOW AN EXAMPLE USING THE SINE FUNCTION (there is also a link purporting to pick the cosine function)]

UNFINISHED