GrafEq - Values and Variables
Macintosh ManualAppendix D. Values and Variables
There are three main groups of values and variables in GrafEq as explained following:
Numbers
Numbers are formed from the ten numeric digits (0 to 9), the decimal point,
and the negation sign. Numbers, or to be precise, digits, can only be numeric values,
and cannot be used as variables.
Numbers can be entered via the computer keyboard, the numeric keypad, or the
easy button floating window.
Tips:
Infinity (oo) is a constant, and can be entered by presing control-8.
Roman Letters
All Roman letters except for e can be used as variables or constants.
e is a predefinied constant in GrafEq, equal to 2.7182818284590452..., and is the
base of natural logarithms.
GrafEq is case sensitive, so uppercase and lowercase letters are considered
different and unique; x and X are not the same.
Roman letters can be entered via the computer keyboard, or the easy button floating window.
Greek Letters
All Greek letters except for p can be used as variables or constants.
p is a predefined constant in GrafEq, equal to 3.1415926535897932..., and is a
half circle’s angle in radian measure.
GrafEq is case sensitive, so uppercase and lowercase letters are not the same;
w and W are two different variables.
Greek characters can be entered via the easy button floating window,
or using the keyboard key combinations listed in figure D.1 following:
| Alpha | A | control-A | a | control-a |
| Beta | B | control-B | b | control-b |
| Chi | C | control-C | c | control-c |
| Delta | D | control-D | d | control-d |
| Epsilon | E | control-E | e | control-e |
| Phi | F | control-F | f | control-f |
| Gamma | G | control-G | g | control-g |
| Eta | H | control-H | h | control-h |
| Iota | I | control-I | i | control-i |
| Theta Variant | J | control-J | | |
| Phi Variant | | | j | control-j |
| Kappa | K | control-K | k | control-k |
| Lambda | L | control-L | l | control-l |
| Mu | M | control-M | m | control-m |
| Nu | N | control-N | n | control-n |
| Omicron | O | control-O | o | control-o |
| Pi | P | control-P | p | control-p |
| Theta | Q | control-Q | q | control-q |
| Rho | R | control-R | r | control-r |
| Sigma | S | control-S | s | control-s |
| Tau | T | control-T | t | control-t |
| Upsilon | U | control-U | u | control-u |
| Sigma Variant | V | control-V | | |
| Pi Variant | | | v | control-v |
| Omega | W | control-W | w | control-w |
| Xi | X | control-X | x | control-x |
| Psi | Y | control-Y | y | control-y |
| Zeta | Z | control-Z | z | control-z |
|
Figure D.1: Greek Alphabet and corresponding input key combinations
Sets
Sets can be
- discrete, containing elements listed within a pair of braces, or
- continuous - continuous sets can contain
- open ranges described within a pair of parentheses, or
- closed ranges described within a pair of square brackets.
Conclusion
To conclude this section of the manual,
following are some additional hints and tips about
GrafEq values:
- GrafEq relations can be specified in a wide latitude:
- Virtually all alphabetical characters are acceptable as variables.
- At the Create View window, any alphabetical characters entered in a relation, as
well as x, y, r, and q can be specified as domain and range variables.
- For cartesian (rectangular) graphs, domain (horizontal axis) and
range (vertical axis) variables default to x and y; for polar graphs,
q and r. All defaults can be modified.
- Hint:
In both cartesian and polar graphs, r defaults to the distance from the origin,
and q to the position angle in radians.
- Some characters are reserved in GrafEq to be values, therefore, they cannot be
used to represent variables. These values include: p, e, oo, as well as
all numeric digits.
- Variable names must be atomic; xy means two variables, and cannot be used as
one variable name.