The code below is from a previous posting that
I answered. You can cut and paste it into your
worksheet, and then play with it to see what the
different commands will do. ?plot, ?textplot,
and ?display will give you more info as to why
the code below does what you asked.

> restart:
> with(plots):

> P1 :=plot (sin(x), x=-3*Pi/2..3*Pi/2,
tickmarks=[0,0], title=`Plot of sin(x)`):

> P2 :=textplot([[Pi,-0.05,`p`], [Pi/2,-0.05,`p/2`], [-Pi/2,-0.05,`-p/2`],[-Pi,-0.05,`-p`]], align={BELOW,CENTER}, font=[SYMBOL,10]):

> P3:=textplot([[-0.1,1.0,`1.0`], [-0.1,0.5,`0.5`],
[-0.1,-0.5,`-0.5`],[-0.1,-1.0,`-1.0`]], align={CENTER,LEFT}):

> P4:=pointplot ([[-Pi,0], [-Pi/2,0], [Pi/2,0],
[Pi,0],[0,1.0],[0,0.5],[0,-0.5],[0,-1.0]]):

> display({P1,P2,P3,P4});

Regards,
Georgios Kokovidis
Dräger Medical

Here is a function that will do the plotting for you, all you have to do is pass the expression that you want plotted and the range, just like you do for plot. Copy and paste this code into your worksheet and you will be able to use the function anywere in your worksheet. Click here to download the worksheet to try it on your computer

When viewing the Worksheet below, the symbols appear as "p". When you download the worksheet it will look better

> trigPlot := proc( thePlot, range )
local start, finish, offset, spacing, truestart, ticks,tick, tickName, pos;
spacing := Pi/2;
start := op(1, op(2,range) );
finish := op(2, op(2,range ) );

ticks := [];
pos := start;
while( evalf(pos) <= evalf(finish) ) do

tickName := convert( pos, string );
tickName := StringTools[Substitute]( tickName, "Pi", "p" );
ticks := [op(ticks), evalf(pos)=tickName];
pos := pos + spacing;
end do:

plot( thePlot, range, axesfont= [SYMBOL],tickmarks = [ticks,default] );
end proc:

Here are some examples of its usage

> trigPlot(cos(x), x=-Pi..Pi);

> trigPlot(sin(x),x=-2*Pi..Pi/2);

> trigPlot(sin(x)^2, x=0..2*Pi);

>

This post was generated using the MaplePrimes File Manager
Download the original worksheet | View worksheet on MapleNet

Please see ?plot,options and look for labels. If you don't want a label on the y axis , you could achieve what you want by altering your plot command to:

plot(f(x), x = -20 .. 20, labels = (["", ""]));

Hope this helps.

J. Tarr