marginsspacing
I added the preamble:
\usepackage[inner=2.5cm,outer=3cm,bottom=2cm,top=2cm]{geometry}
But it produces weird spacings like this:
It seems the problem occurs because the bottom margin is forced to be exactly 2cm. So, is it possible to specify the bottom margin to be at least 2cm?
For the margins use the geometry package. For your particular example use
\usepackage[inner=2.5cm,outer=1.5cm,bottom=2cm]{geometry}
Check the documentation of this package for more details and other options!
For the line spacing use setspace. Again for your example
\usepackage{setspace}
\onehalfspacing % or \doublespacing
If I print the document based on the code below on my printer to A4-paper (on Scientific Linux 6, Adobe Reader with the settings in the image below) I get a left margin of 3 cm, a top and bottom margin of 2.6 or 2.7 cm and a right margin of 2 cm.
I quickly measured with a cheap plastic ruler, so within an uncertainty of 2 mm I get the same as your requirements :)
It thus seems to be a printer problem on your side.
And - only as a snide remark - it might be good to try to pursue your school that these margins (and font settings) don't really make sense for a nice document. But that's completely unrelated to your problem.
\documentclass[12pt,a4paper,oneside]{article}
\usepackage{setspace}
\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage{fancyhdr}
\usepackage{tabularx}
\renewcommand{\rmdefault}{phv}
\renewcommand{\sfdefault}{phv}
\usepackage[a4paper,left=3cm,right=2cm,top=2.5cm,bottom=2.5cm]{geometry}
\onehalfspacing
\usepackage{lipsum}
\begin{document}
\lipsum
\end{document}
Best Answer
This may depend on what surrounds the equation, which includes what follows it on the following page. The reason here is that LaTeX inserts some stretch between document components in an attempt to optimize the layout, possibly resulting in the display you see.
Using
\raggedbottommight fix this, or issuing a manual page break. But leave such manual intervention to end of your typesetting adventure...