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The expression tree
The expression tree is a diagram showing how the Equation Writer interprets
an expression. See Appendix E for a detailed example.
The CURS function
The CURS function (
@CURS
) in the Equation Writer menu (the
B
key) converts
the display into a graphical display and produces a graphical cursor that can
be controlled with the arrow keys (
š™—˜
) for selecting sub-
expressions. The sub-expression selected with
@CURS
will be shown framed in
the graphics display. After selecting a sub-expression you can press
`
to
show the selected sub-expression highlighted in the Equation writer. The
following figures show different sub-expressions selected with and the
corresponding Equation Writer screen after pressing
`
.
Editing algebraic expressions
The editing of algebraic equations follows the same rules as the editing of
algebraic equations. Namely:
•
Use the arrow keys (
š™—˜
) to highlight expressions
•
Use the down arrow key (
˜
), repeatedly, to trigger the clear editing
cursor . In this mode, use the left or right arrow keys (
š™
) to
move from term to term in an expression.