The evaluator is used to evaluate numerical expressions either because the user prefers it to the keypad calculator, or in order to use the additional flexibility of using defined constants or expressions that are not available in the keypad calculator.
The Function Evaluator consists of three separate components: the Expression Input Box, the Result Box, and the History List Box.
The Expression Input Box allows the user to type mathematical expressions using common ASCII notation for mathematical operations. Numbers in either fixed point or scientific notation are allowed.
Plus (+), minus (-), multiply (*), divide (/), power (^), and common functions such as sin, cos, tan, log, ln, are all recognized correctly. Parentheses are used to group logical items and to mark objects of functions, such as sin(1.4). Trigonometric functions use radians as a default.
The following table lists the notation for various expressions and functions for the Evaluator.
| Function | Syntax | Example |
|---|---|---|
| Times | * | 3*4 |
| Divide | / | 3/4 |
| Add | + | 3+4 |
| Subtract | - | 3-4 |
| Exponentiation | ^ | 4^2 |
| Sine | sin( ) | sin(2.5) |
| Cosine | cos( ) | cos(2.5) |
| Tangent | tan( ) | tan(0.5) |
| ArcSine | asin( ) | asin(0.5) |
| ArcCosine | acos( ) | acos(.23) |
| ArcTangent | atan( ) | atan(.67) |
| Hyperbolic Sine | hsin( ) | hsin(2) |
| Hyperbolic Cosine | hcos( ) | hcos(4) |
| Hyperbolic Tangent | htan( ) | htan(2) |
| Hyperbolic Arcsine | hasin( ) | hasin(0.5) |
| Hyperbolic Arccosine | hacos( ) | hacos(3) |
| Hyperbolic Arctangent | hatan( ) | hatan(.6) |
| Square Root | sqrt( ) | sqr(4) |
| Factorial | ! | 5! |
| e to the x | exp( ) | exp(-2.5) |
| Logarithm | log( ) | log(3) |
| Natural logarithm | ln( ) | ln(2) |
After typing an expression into the Input Box, you evaluate it by pressing ENTER. It is not necessary to use the = sign when evaluating an expression. The result is displayed in the result box, and spoken if speech is turned on. The expression and result are also entered in the history box for future reference. In addition, previously entered expressions can be recalled by using the UP or DOWN ARROW keys.
Exercise 2.10. Explore the Evaluator's Expression Input Box.
Constants and expressions may be defined by writing name=value and then pressing CTRL ENTER. The name may be any combination of characters that doesn't have a pre-defined meaning (such as sin or ln), and the value may be anything that can be evaluated, including expressions whose variables have been previously defined. Any variable that has not been defined is assigned the value zero. Defined constants are included in the history box.
If you redefine a constant or expression, a dialog box appears asking if you really want to do this. Press y or ENTER if you do, and n if you do not.
Exercise 2.11. Constant definition in the Expression Input Box.
This box contains the numerical result of the expression that was evaluated. This number may be browsed digit by digit with the RIGHT/LEFT ARROW keys. HOME and END take you to the beginning or end of the number.
All previously evaluated expressions are stored, along with their results, in a list for the user's convenience. Individual entries in this list may be browsed in the same manner as in the Result box. The UP and DOWN ARROW keys move up and down through the entries in the history list. HOME and END move the cursor to the beginning and end of an entry in the list. CTRL HOME and CTRL END move the cursor to the beginning and end of the list.
Exercise 2.12. Explore the Result and History Boxes.
Next: Section 2.5. Data Set Tab Pages
Last: Section 2.3. Calculator Tab Page
Index