# Removing extra vertical space between equations and new lines

So this has always bothered me, and I'd like to find out how to fix it once and for all. How can I prevent additional lines before and after equations, align environments, etc., from adding additional vertical space in the resulting PDF? For example, the following looks fine and dandy when compiled,

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\begin{document}

In lectures, the following formula was derived using residues:
\begin{align*}
\sum_{i=1}^n \frac{1}{n^2} = \frac{\pi^2}{6}
\end{align*}
Euler found this in 1735, 90 years before Cauchy introduced residues.

\end{document}


yielding: whereas a small change to the code,

In lectures, the following formula was derived using residues:

\begin{align*}
\sum_{i=1}^n \frac{1}{n^2} = \frac{\pi^2}{6}
\end{align*}

Euler found this in 1735, 90 years before Cauchy introduced residues.


yields this hot garbage:

This also happens when I use the  delimiters in the particular environment I use, but not in this clean slate. Anywho, any help appreciated. Cheers.

Edit: I like to space my .tex file like this for organization.

• Welcome to TeX.SX! So what do you want? The first spacing, also if you put paragragraph breaks in between? – TeXnician Nov 24 '17 at 5:26
• You can add % sign ti the beginning if the lines. That way there are no empty lines for TeX, but the code is more readable – Michael Fraiman Nov 24 '17 at 5:37
• @TeXnician I would like to have the first spacing, even if I have paragraph breaks in between. – Möbius Dickus Nov 24 '17 at 5:40
• @MichaelFraiman I would prefer a solution that wouldn't require additional code every time I require an equation --- preferably, a more global solution. – Möbius Dickus Nov 24 '17 at 5:41
• You may blithely claim that adding two paragraph breaks -- remember: a fully-blank line creates a paragraph break -- is "a small change", but this belief is both unwarranted and misguided. Paragraphs are absolutely fundamental to the way TeX builds up the elements of a page and assembles them into a page. In your first example, TeX finds a single paragraph; in the second example, in constrast, TeX finds three paragraphs, the middle paragraph consisting of a displayed equation that's not tethered to the material that precedes it. Do please read up on the importance of paragraphs. – Mico Nov 24 '17 at 5:54