I am using subequations environment with align and with eqnarray. In both cases, a large vertical space appears between text and equations. I don't know how to fixed that space to be the same as in equation environment…
Example:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\begin{document}
Teniendo en cuenta que podemos relacionar el ángulo $\theta$ (figura tal) con las componentes del vector normal: This is tooo much space:
\begin{subequations}
\begin{eqnarray}
a &=& \sin \theta \\
c &=& \cos \theta = \sqrt{1 - a^2}
\end{eqnarray}
\label{eqangulos}
\end{subequations}
Podemos escribir el parámetro del rayo como... I want something like in equation environment:
\begin{equation}
p = \frac{\sin \theta}{C} \left(1 + \frac{u \, \sin \theta}{C} \right)^{-1}
\label{eqparametro3}
\end{equation}
This is good...
\end{document}
Best Answer
I have two suggestions:
Don't allow paragraph breaks between text and a displayed equation. Remember that an all-blank line creates a paragraph break. (Depending on the material at hand, creating a paragraph break after a displayed equation can be ok, though.)
Don't use
eqnarray
environments. Instead, usealign
environments.