Getting Started with TI InterActive! 55
TII_GettingStarted.doc Getting Started with TI InterActive! Karen Davis Revised: 6/15/04 2:00 PM Printed: 6/15/04 3:39 PM Page 55 of 63
The TI InterActive! math system is dynamic
and performs updates of all variables whenever
a new object is defined, modified, or moved.
This feature enables new ways in which to
illustrate ideas and concepts. It may also
require some experience in order to know what
to expect.
Each object has an evaluation point that determines when its
information is available for evaluation by the math system.
Evaluations occur in a specific order.
Objects whose evaluation point appears above or to the left
of other objects’ evaluation points are evaluated first.
Subsequent objects are evaluated in this spatial order until all
objects in the document are evaluated.
This evaluation occurs many times during the course of creating
or editing a document. The example below illustrates the
importance of the math evaluation order.
Document 1
Document 2
In
Document 1
,
a
is defined as
20
and
30
in consecutive Math
Boxes on the same line. In
Document 2
, the definition order is
reversed, and
a
is defined as
30
and
20,
again
in consecutive Math
Boxes on the same line. The position of the second Math Box is
significant to the evaluation of the third Math Box, which
contains the expression
factor(a)
. In the first document,
a
is equal
to
30
when the third Math Box is evaluated. In the second
document,
a
is equal to
20
when the third Math Box is evaluated.
Math updates
