When plotting a continous function that looks something like a square wave, for example like this:

f:=x->piecewise(0<x<Pi,0,Pi<x<2*Pi,Pi);
a:=0: b:=2*Pi: p:=b-a:
fp:=f(x-floor( (x-a)/p)*p);
plot(fp,x=-6*Pi..6*Pi,discont=true);

Is there some way to show dashed vertical lines at the points of discontinuity?

If we have a piecewise continous 2*Pi-periodic function

h(t)=e^(2*t) when 0 < t < 2*Pi

How can we plot it? It should look something like this:

I.e. I want to be able to just set an interval and then it automatically plots the function with the specified periodicity.

If we a complex number in Maple, like for example:

I*b+a+x+I*y+I^2*c

How can we make maple rewrite it like this?

a+x-c+I*(y+b)

I tried using the comands Re(%) and Im(%) but Re just gives the whole expression again and Im gives 0.

When I write in maple the following:

x*(x+y)

What do I need to write to make maple make the operation that will evaluate the expression and show the following?

x^2+x*y

simplify(%) or evaluate(%) only shows it the same way it was inputted to start with.