TouchPlot 3.2 will soon replace 3.1 version. While TouchPlot 2.2 added important simplifications in the formula editor, TouchPlot 3.2 adds even more.

Keyboards are now six rows tall :

fedit

Most of the buttons should be self-explanatory but some deserve some information :

on the first row, first button change action for most of the buttons. The two arrows next to it allows one to select one part of a formula for selection, moving along the formula one item at a time. Note that when 2nd is enabled, the left arrow selects the entire formula, and the right one deselects...

The Vars button adds one row to insert a variable amongst a,b,c,d. Those variables can be adjusted with the Constants menu, as well as live on the graph view if sliders for a,b,c or d were enabled.

The last button is the undo button, allowing one to remove the last entered item. Note that when there is a selection, its action will be to delete the selection, always asking for confirmation. Note too that when deleting a selection, the undo trace is deleted as well, so the undo button will become inactive, and it will only undo subsequent insertion of items in the formula.

Note that in the second row is :

Num

which allows one to enter a numeric const in a formula. (A numeric pad will appear for that.)

For single digit number, such as 1,2,3,4,5, some shortcuts have been provided to speed up formula entry.

The main difference with previous versions of TouchPlot as regards the formula editor is the possibility offered to select a part of a formula.

Supposing one is defining h function, by composing :

expx

one gets

ex5

then using the left selection arrow, we select the last entered item, that is, x and get :

ex6

In such a mode (selection mode), the behavior of the editor is the following :
- the undo button deletes the selection
- adding a const (a variable, a number) it is multiplied to the selection
- entering a function inserts the function, making the selection the operand of the function inserted. (so inserting sin in the example above, one gets exp(sin(x)) of course).
- entering an operator makes the selection the first operand of the operator, so inserting + in the example above we get this :

ex7

You notice of course the change of color. There is no selection anymore, but a red color showing the editing is now locked inside the exponential function. Subsequent entries will complete the exponential argument. To exit the lock, just use the right arrow.

It is now very easy to enter an expression such as (2x^3+x+1)/(x^2-x+1). It is of course still possible to use polish notation from beginning to the end, but the fastest here would probably be :

divideleftSelectleftSelect

so that we get :

Image 4

By selecting the numerator, we will first fill the blank with the first item, and remain editing the numerator until we decide otherwise.

2xpowersecond3plusxplus1

So we have the numerator, and the formula display shows :

fraction2

Now that we finished entering the numerator, we exit the lock with

rightSelect and we get fraction3

Notice that the lock has not disappeared, but has just moved to the denominator, which is perfect for what we need now... We just enter the denominator then with :

xpower2minusxplus1

There are many other equivalent ways to enter this function with touchplot 3.2... I let you find them !