Texas Instruments Titanium TI-89 - (Prime) 2 Nd Key; _ (Underscore) Key

910 Appendix A: Functions and Instructions
( magnitude 

 angle ) ⇒
⇒⇒
⇒ complexValue (polar input)
Enters a complex value in (rq) polar form. The
angle is interpreted according to the current Angle
mode setting.
In Radian angle mode and Rectangular complex
format mode:
5+3 i ì (10p/4) ¸
5
ì 5ø 2+(3ì 5ø 2)ø i
¥¸ ë 2.071…ì 4.071…ø i
¡
¡¡
¡, ', " 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^(ë 1/2) and y(0)=0 and
y'(0)=0,t,y)
¸
2
øy
3/4
3
=t
_ (underscore) ¥  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
module about constants and measurement units.
You can press 2
9 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_)