I'm using Maple 12.02 on a Mac under OS X.4.11 (Tiger).

Most times when I print a worksheet, or preview it or save it to a PDF, the result includes one or more blank pages.  That is, they are blank except for the vertical lines at left and right margins.  All of the worksheet material is printed, but blank pages are inserted seemingly at random.  I've found no extraneous markings on the worksheet that might cause this, and I haven't figured out how either to prevent it or to delete the blank pages from the PDF file.

I know this sort of simplify question has been asked many times, but I still don't seem to have 'got it'.  In a nutshell, there's a conservative real 2-D vector field (cartesian X,Y coordinates) with an extra non-positive parameter Z, and Maple 12 is able to compute the scalar potential.  But it presents it in a long (6 lines), perversely complicated form, involving the imaginary sqrt(-Y^2).  I tried to show it here using the Maple leaf Tag and pasting the expressions there, but all I got was indecipherable ascii.  The vector field X and Y components are

I'm having trouble figuring out how to find the 2-D scalar potential of a 3-D vector field projected onto a plane.  The vector field is computed on the plane, coordinates (X,Y), as a vector function with arguments (X,Y,u), with 'u' being a parameter.

After invoking the VectorCalculus package and specifying

    SetCoordinates(cartesian[X,Y]),

Maple 12.02 on a Mac running OS X.4.11.

As a first step trying to simplify a longish expression (pasted together from separate parts), I copy it to a scratch worksheet and ask it be displayed.  It shows up (2D Math mode) with the front part of it missing.  When I step through the expression with the arrow keys, the mode stays the same, so there doesn't seem to be break in it.  Here's the expression and its displayed form, pasted into the box that appears on clicking on the Maple leaf icon above this message input area:

To evaluate some real integrals I use the 'assume' instruction to make sure all the quantities are real.  But Maple 12 can't seem to deduce the obvious inequalities from this - testing for them gives a FAIL result.  Here is a minimal example:

    assume(X,real, Y,real, w>0);

    is( (X+w)^2 + Y^2 >= 0);