Question: a couple of newbie questions

Hi all. I am using Maple 18.

1. How can I make maple NOT plot discontinuties with a vertical line? For example, plotting y=tan(x) displays vertical lines. Is there a setting to turn this off permanently?

2. When I type y=sin(x-Pi/2) and press enter, y = -cos(x) is displayed in blue. I am sure they are both the same thing, but I would like to see the expression that I typed, not an alternate expression that Maple wants to display.

3. Why do some expressions require a ; at the end, whilst others don't? Ie. y = sin(x) and y = 1+sin(x) do not, but y=2*sin(x) results in a "Warning, inserted missing semicolon at end of statement"

4. Is there a section on Mapleprimes(this site) where new users can ask questions? I would like to browse it to see what sort of problems other new Maples users have encountered. I am sure that my above questions may have been asked a few times over the years by newbies like myself.

Thanks in advance. :)