4.1 Rules of Thumb: How to interact with Maple

Start Maple by typing xmaple in a terminal window, or find an entry for Maple on your root menu. If you can't figure out how to start Maple, ask your lab demonstrator for help.

Typing stuff in

Every time Maple is waiting for you to type some input, you will see a prompt, which is a greater-than sign (>) at the left side of the Maple window. In Maple, almost everything you type is, in one way or another, a request to evaluate an expression. Some expressions might be long, so Maple allows you to type them across several lines. To tell Maple the input is complete, you have to put a semicolon (;) at the end of the completed expression. For example, the input line

> a + b;

is a request to evaluate the expression a+b. On the other hand, Maple considers the following input to be exactly identical to the above:

> a
> +
> b
> ;

When you enter an expression terminated by a semicolon, Maple does its best to evaluate the expression, using any number of methods. When it gets a result, it prints out the answer, and then returns you to the prompt for more input. This cycle of input and evaluation repeats for the entire Maple session; it is how things get done in Maple.

In summary then, Maple won't go to work until it sees a semicolon from you, to signal the end of the current expression. Incidentally, you may also use a colon (:) in place of a semicolon, with the only difference being that Maple will not display the result of evaluating your expression. What's nice about this is that you never have to worry about forgetting the semicolon. If you forget it, just type it on the next line.

Naming things

You might be used to seeing Greek letters and various other symbols used in your math courses, but since Maple requires you to type everything on a keyboard, all that has to be translated into a text name, so write alpha in place of

, for example. Various standard operations such as integration also have spelled-out names. Since it is impossible to type in

Maple provides the builtin functions int, exp (and many others!) and the above would be entered as

> int(exp(-x^2/2), x=0..infinity);

Here are some further reminders about entering things in Maple:

Multiplication is always written '*', as in 2 * x.
Division is written '/', as in x/y = z.
Subscripts are written in brackets, so is written x[n].
Exponentiation, or "x to the power n" is written x^n, or x**n.
The usual order of algebraic operations is applied: multiplication and division are performed before addition and subtraction, and so on. Parentheses can be used to group expressions which don't follow this rule. For example,
> 5 + 6 * 7;
evaluates to 47, and not to 11*7 = 77, as it does on some basic pocket calculators. If you really want Maple to add 5+6 before multiplying, enter
> (5+6) * 7;
The built-in constant Pi holds the value of pi: 3.14159...

Keith Orpen, who is still writing this, would like to hear your comments and suggestions.