6
Chapter 1: First Steps
Simplify using
.
This is different from what an “ordinary” calculator would produce. A mathematician once
asked:
“How do you recognize a mathematician?”
and suggested the following answer:
“A
mathematician considers expression #5 a beautiful result.”
Most students strive to replace
such an expression by the corresponding floating point approximation. D
ERIVE
can do this as
well: Highlight expression #4 so that you can apply a different command to it.
Highlight expression #4 by moving the mouse pointer anywhere in the row occupied by the
expression, then clicking the left mouse button.
Selecting an expression with the mouse button is one technique of highlighting it. An alternative
technique is first to move the focus into the algebra window (if necessary) using the
(Esc)
key,
then using the cursor keys
(½)
or
(¼)
to move the highlighting one expression up or down.
Approximate using the Command Toolbar’s
Approximate
button
.
While an expression is highlighted, the Status Bar’s second pane shows the automatically
generated expression annotation. The third pane shows the computing time in case the expres-
sion was obtained as a result of a computation. For expression #6 this is:
The automatically generated annotation explains how the expression was obtained.
Approx(#4)
means that the expression was obtained by applying the
Approximate
button (or
command) to expression #4. The computation time displayed in the third pane,
0.000s
,
indicates that the calculation took less than 0.001 seconds (the time may be different on your
computer).
Highlight expression #4, . . .
. . . then expression #5.,
The annotation of expression #4,
User
, means that it was entered by the user; the annotation of
expression #5,
Simp(#4)
, indicates that the expression was obtained by applying the
Simplify
button (or command) to expression #4. The first pane is always available for messages
associated with a menu item, button, or command status.
D
ERIVE
worksheets also can include text and other objects. The easiest way of entering text is via
the Command Toolbar’s
Insert Text
button
. New expressions are added at the end of the
