General Hints and Clues about Maple

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A summary of some points which come up in Easy 1.

Start of Easy1    ( for Maple V release 4. Things are slightly different in Release 3.)

The restart command resets all previous assignments and starts over.

A # on a line of Maple code lets you put comments on that line. The danger is that text from the comment may 'wrap around' and wind up on a separate line if the program is re-opened. The line coming up has a comment on it.

Assignment statements use ' := ' like in pascal . We will assign 3 t + 4 t^2 to x. This is not a 'formal' definition of a function, but the informal definition works well in almost every situation.

Plotting a function. Execute the command plot(x,t=0..4); . (click anywhere on the line). After a moment, a plot should appear.

Move the cursor around over the plot to a spot where you want the coordinates, then click the mouse. This gives the coordinates at the lower left (release 3) or upper left (release 4). It is very handy for identifying specific features of graphs. For practice, locate the value of t when x=5.0. (It's a little tricky, since X,Y are generic on the graph and in this case Y is playing the role of x, and X is playing the role of t. It should come out near t=0.8)

To ask for help on a topic or function just type '?' and the item. The next command asks for help on the plot command. Most help screens have examples at the bottom. You can cut and paste right into your program from help if you wish.

When we click in the plot, we find the x,y values (upper left corner in release 4, lower left corner in release 3) where xand y are equal (around x=1.33, y=11)

In the statement coming up, the equality statement is just a plain ' = ' ; there is no semicolon with it. This represents equality and not assignment.

Find the t value where x and y arequal; notice use of '=' without the semicolon in the solve command

This is not so helpful, so we get a floating point evaluation.

Substitute t back into y to get the y value using the 'subs' command (2 ways)

xval and yval should be nearly the same.

Exercises for the user

1) Find the intersection(s) of y=1-3x and y=0.5+x^2; [ answer: around (0.16,0.53) and around (-3.16,10.5) ] ;

2) policeman and speeder

End of easy1.mws