Texas Instruments TI-89 Manual page 4

TI 89-4
The TI-89 can switch to scientific notation when the number is too
large for the display area in a table or graph. The TI-89's symbol for
−
−
6
"times 10 " is
E
scientific notation for 0.0000014675. Enter
The result
1.5 28
E
28
1.5(10 ). In the history area, an arrowhead ( ) that points to the
right at the end of a number means that the number or expression
continues. Highlight the number or expression and press
scroll and see the rest of it. Press
4. STORI NG VALUES It often is beneficial to store numbers or expressions for later recall. To
store a number, type the number, press
age location, and then press
statements. Note that when you join statements with a colon by pressing
of the last statement is shown as a result.
Store 5 in a and 3 in b, and then calculate 4a – 2b.
To recall a stored value, press
expression or value is stored, and then press
•
Storage location names on the TI-89 can be from one to eight characters long and use letters
and numbers, but they must begin with a letter. You cannot name what you are storing with
the same name that the TI-89 already uses for a built-in variable (such as
•
Whatever you store in a particular memory location stays there until it is replaced by some-
thing else either by you or by executing a program containing that name. It is advisable to
use single-letter names so that the values will be cleared when you begin with
NOTE: The TI-89 allows you to enter upper and lower case letters, but it does not distinguish
between them. For instance,
type a lower-case letter, press
under the entry line). To type an uppercase-letter, press
appears under the entry line) before typing the key corresponding to the letter.
If a variable is undefined (i.e., you have not stored a value in it), it
is treated as an algebraic symbol. If a variable is defined, its value
replaces the variable when you enter an expression containing that
variable. It is best, as we see in later chapters, to leave the names x
and y as undefined variables.
WARNI NG: You must be very careful when entering expressions containing variables. In the
next-to-last expression shown on the screen above, the TI-89 assumes "ax" refers to the name of a
single undefined variable. To tell the calculator that you want to multiply the variable a by the
variable x, you must use
−
. So, means 1.4675 * 10
6 1.4675 6
E
means 15,000,000,000,000,000,000,000,000,000 =
▼ to return to the entry line.
STO
Join several short commands with a colon between the
ENTER .
, type the letter in which the
alpha
VOL, Vol, VOl, vol, voL
before typing a letter key (note that a lower-case
alpha
between the letters. Also, because 5 has been stored to a, the TI-89
−
6
, which is
by pressing
" " EE .
E
► to
, type the letter(s) corresponding to the stor-
alpha
ENTER .
, and so forth all name the same variable. To
(note that an upper-case
alpha
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Chapter 1
, only the value
2nd 4
( : )
or ).
LOG ans
.
NewProb
appears
a
A