Editing and Evaluating TwoDimensional Expressions

When you see a twodimensional expression on the screen, you can edit it much as you would edit text. You can for example place your cursor somewhere and start typing. Or you can select a part of the expression, then remove it using the Delete key, or insert a new version by typing it in.

In addition to ordinary text editing features, there are some keys that you can use to move around in twodimensional expressions.

Ctrl+.select the next larger subexpression
Ctrl+Spacemove to the right of the current structure
move to the next character
move to the previous character

Ways to move around in twodimensional expressions.

This shows the sequence of subexpressions selected by repeatedly typing Ctrl+..


Nullevaluate the whole current cell
Shift+Ctrl+Enter (Windows/Unix/Linux) or Cmd+Return (Mac OS X)
evaluate only the selected subexpression

Ways to evaluate twodimensional expressions.

In most computations, you will want to go from one step to the next by taking the whole expression that you have generated, and then evaluating it. But if for example you are trying to manipulate a single formula to put it into a particular form, you may instead find it more convenient to perform a sequence of operations separately on different parts of the expression.

You do this by selecting each part you want to operate on, then inserting the operation you want to perform, then using Shift+Ctrl+Enter for Windows/Unix/Linux or Cmd+Return for Mac OS X.

Here is an expression with one part selected.


Pressing Shift+Ctrl+Enter (Windows/Unix/Linux) or Cmd+Return (Mac OS X) evaluates the selected part.


The Basic Commands y=x tab in the Basic Math Assistant, Classroom Assistant, and Writing Assistant palettes also provides a number of convenient operations which will transform in place any selected subexpression.

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