Texas Instruments TITANIUM TI-89 User Manual page 667

You can:
Refer to a function or equation
defined elsewhere.
Notes:
• Do not use system function
names (such as
as simple variables (
• Be careful with implied
multiplication. For example,
a(m2+m1)
is treated as a
function reference, not as
a † (m2+m1)
.
Type an expression without an =
sign.
Note: When you define the
variables, you can either define
exp or solve for it.
Recall a previously entered
equation or open a saved
equation.
Note: After you press
current equation is stored
automatically to the system
variable eqn.
Numeric Solver
For example:
Suppose you defined y1(x) on either
the:
•
y1(x) r1( q )
or )
y1 r1
or ).
•
In the Numeric Solver, you then would
enter:
y1(x)=0 or y1(t)=0, etc.
e+f
N
After you press
is set equal to a system variable called
exp and entered as:
exp=e+f
Refer to the applicable heading later in
this section.
¸
the
Y= Editor:
y1(x)=1.25x † cos(x)
– or –
Home screen:
Define y1(x)=1.25x
The argument does
not have to match
the one used to
define the function
or equation.
ln(g)
¸
, the expression
N ln(g)
† cos(x)
667