536 Appendix A: Functions and Instructions
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 536 of 132
¡, ', " 2“
key (¡), 2È
key ('), 2É
key (")
dd¡mm'ss.ss" ⇒ expression
dd A positive or negative number
mm A non-negative number
ss.ss A non-negative number
Returns dd+(mm/60)+(ss.ss/3600).
This base-60 entry format lets you:
• Enter an angle in degrees/minutes/seconds
without regard to the current angle mode.
• Enter time as hours/minutes/seconds.
In Degree angle mode:
25°13'17.5" ¸25.221...
25°30' ¸51/2
' (prime) 2È
key
variable '
variable ''
Enters a prime symbol in a differential
equation. A single prime symbol denotes a
1st-order differential equation, two prime
symbols denote a 2nd-order, etc.
deSolve(y''=y^(ë1/2) and
y
(
0
)
=0 an
d
y'
(
0
)
=0,t,y
)
¸
2øy3/4
3 =t
_ (underscore) TI-89: ¥ key TI-92 Plus: 2 key
expression_unit
Designates the units for an expression. All
unit names must begin with an underscore.
You can use pre-defined units or create
your own units. For a list of pre-defined
units, refer to the chapter about constants
and measurement units in this book. You
can press:
TI-89: 2 9
TI-92 Plus: ¥À
to select units from a menu, or you can
type the unit names directly.
3_m 4 _ft ¸9.842…ø_ft
Note: To type 4, press 2.
variable_
When variable has no value, it is treated as
though it represents a complex number. By
default, without the _ , the variable is
treated as real.
If variable has a value, the _ is ignored and
variable retains its original data type.
Note: You can store a complex number to
a variable without using _ . However, for
best results in calculations such as cSolve()
and cZeros(), the _ is recommended.
Assuming z is undefined:
real(z) ¸z
real(z_) ¸real(z_)
imag(z) ¸0
imag(z_) ¸imag(z_)