@acer Dear acer,
Thank you very much for this. I'll get onto this once I get back to work after the Easter break.
Meanwhile, I hope the next update of Maple will incorporate all these changes. I cannot understand why you need to as Carl Love suggested use a "precalculus" package to get things working or as acer has suggested manipulate the codes, etc. You would imagine that when one asks Maple to plot a graph, it would plot out exactly what you would get when sketching these by hand without having to get around things in order to get to the destination. Alas! :(
P.S. These are for primary school students, and so the easier way to do things, the better it is. Hence, we have used right-click on the output of the function and choosing "Plots" and then select "2-D Plot of Right Side" as it is the quickest route for these 11 year old kids.
Thanks to all who have answered!! Very much appreciated!
Have a good Easter everyone! :)