Articles of equations

How can I produce the symbols representing sign conventions for forces and moments in mechanical equilibrium equations?

Engineering texts often use a straight or curved arrow paired with a “plus” sign to indicate the sign convention for forces and moments at the beginning of an equilibrium equation. For example, see the below image from an engineering textbook, where I have circled in red three of these symbols: My experience has been that […]

How do I get a equation to not break the margin?

How do I get this equation to not break the margin? I have tried different things, do I need to used something else then align? \begin{align*} \int_{\R^2} \1_{[-1,1] \times [0,\pi)} (p, \alpha) \Theta (\D(p, \alpha)) &= \int_{\R^2} \1_{[-1,1] \times [0,\pi)} (p, \alpha) \Big( \frac{L_A}{\pi} \lambda \times \lambda \Big) (\D p,\D \alpha) \\ % &= \frac{L_A}{\pi} […]

split an equation

I have the following equation \documentclass{article} \begin{document} \begin{equation} \left\{\begin{array}{l} W_1=N_c^ * w_1^c + N_s^ * \left( {w_1^s + 2w_2^s + w_3^s} \right) \\ W_2= N_s^ * \left( {w_2^s + w_3^s + w_{11}^s + 4w_{22}^s + w_{33}^s + 4w_{12}^s + 4w_{23}^s + 2w_{13}^s} \right)+N_c^ * w_{11}^c \\ W_3=\left( {N_c^ * w_1^c + N_s^ * \left( {w_1^s […]

General way to split a line by a rule of thumb and displaying results

The following is to construct illustrations for concepts of frequency of a properly sampled outcome if any such frequency exists. Doing such illustrations is tedious and liable to error by hand … so it’s best to make a pair of macros and make a macro out of them that does the following: Suppose I have […]

Centered set of equations with single numbering

If I want a set of centered equations, \begin{gather} \end{gather} does the job: \begin{gather} i^2 = j^2 = k^2 = -1\\ ij = -ji = k \end{gather} If I want a set of equations with single numbering, \begin{split} \end{split} does the job: \begin{align} \begin{split} i^2 = j^2 = k^2 = -1\\ ij = -ji = […]

Problem putting matrix operations in an equation

Possible Duplicate: Errors in matrix equation? I’m trying to use official equation container for the first time, and it’s giving me some trouble. I have this equation of a simple matrix operation, and LaTeX isn’t liking it. What’s wrong with this statement? \begin{equation} y = \begin{bmatrix} T & I \end{bmatrix} \begin{bmatrix} a \\ e \end{bmatrix} […]

framed equations

I’m aware of possibilities to frame an “important” equation in Latex as the one suggested in mathmode for instance but I thought it would be nice to have a dedicated environment instead of putting frames or boxes around equations on the fly. So I came up with what follows by just adapting the existing equation […]

Why do these three changes fix this equation-numbering error?

When I use \equation…\endequation instead of \begin{equation}…\end{equation}, all equations have the same number (I know this isn’t best practice for environments; I’m trying to understand the underlying behavior), as in the following example. \documentclass{article} \usepackage{amsmath} \begin{document} The first equation is \equation \label{pyth} a^2 + b^2 = c^2. \endequation The second equation is \equation \label{quad} x […]

Aligning a row of explanations for equation

I was advised to repost the question. I try and give as much input as possible. Currently I use this code \begin{flalign*} \noindent \tab \rho \textsubscript{KOH} & = \num{2.04}\,\si{\g\per\cubic\cm} &\\[-1pt] \text{M}\textsubscript{KOH} & = \num{56.10}\,\si{\g\per\mol} &\\[-1pt] \text{c}\textsubscript{KOH} & = \num{0.05}\,\si{\mol\per\L}\\ \end{flalign*} This results in this I want the = and fractions to be aligned. Svend gave […]

Arrow from last line of equation to the first

I would like to have something similar to the arrow in this picture: Is this possible to include without a lot of coding? At the moment the code is: \documentclass[10pt,a4paper]{scrbook} \usepackage[T1]{fontenc} \usepackage[english]{babel} \usepackage{amsmath} \begin{document} \begin{equation} \begin{split} & ^\text{1}\text{H} + {}^\text{1}\text{H} \rightarrow {}^\text{2}\text{H} + \text{e}^+ + \nu \\ & ^\text{2}\text{H} + {}^\text{1}\text{H} \rightarrow {}^\text{3}\text{He} + \gamma […]