Appendix A: Functions and Instructions 275
¡, ', " 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) ¸
2øy
3/4
3
=t
_ (underscore) @ ¥ q key H 2 q 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
H ¥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 p.
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_)