{equations} is about the various environments to typeset displaystyle mathematics, e.g. equation and {align}. For general questions about mathematical typesetting use {math-mode}. Both tags are possible on the same question.

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315
votes
8answers
32k views

Why is \[ … \] preferable to $$ … $$?

I've heard that you should use \[ ... \] for displayed equations instead of $$ ... $$, but why is that? I'd assumed that it's so that you can more easily tell which are starting and which are ending ...
118
votes
5answers
179k views

eqnarray vs align

Motivation I want to include a list of related equations, say, for a proof, in my LaTeX document. As far as I know, I have two good options, eqnarray and align. Question What is the difference ...
24
votes
2answers
10k views

Left/Right across multi-line equation

I have a multi-line equation that I want to have matching sized parentheses. The advice I read online was to use \left( equation \right. \\ left. rest-of-equation \right) . However, this syntax leaves ...
85
votes
4answers
22k views

What are the differences between $$, \[, align, equation and displaymath?

I once learnt, that it is uncool to use $$, but why is that? Why does \[ not act as a abbreviation to \begin{align}? I noticed, that there is a difference, since one cannot use & and \\ inside a ...
108
votes
5answers
239k views

How can I split an equation over two lines

I am having the following equation: \begin{equation} Q(\lambda,\hat{\lambda}) = -\frac{1}{2} P(O \mid \lambda ) \sum_s \sum_m \sum_t \gamma_m^{(s)} (t) \left( n \log(2 \pi ) + \log \left| C_m^{(s)} ...
58
votes
2answers
31k views

Separate long math text under sum symbol into different lines?

I have the following equation, where there is a lot of stuff under the sum symbol: \begin{equation} d(\vec{x},\vec{y})= \sum_{Z_{xy}\in\vec{Z}_{xy},\forall x\in\vec{x},\forall y\in\vec{y}} ...
72
votes
2answers
82k views

How to write conditional equations with one-sided curly brackets [duplicate]

I want to write a conditional expression such as the following. What is the best way to express such conditional expressions in Latex?
51
votes
4answers
11k views

align vs equation

I always use align in my documents, and avoid equation. Is there anything wrong with that? My reasoning behind this: align > equation, so why not use it?
20
votes
1answer
3k views

Changing the appearance of equation numbers with amsmath

For equations in my document, I use the facilities of the amsmath package. In order to make the equation numbers more eye-catching, I want them to be in boldface and a little bit indented to the ...
69
votes
3answers
35k views

How to get only one vertically centered equation number in align environment with two equations

What I have are two equations with align and I want one single equation number to refer to this system of equations. To illustrate, I have \begin{align} dr_t &= \kappa ( \theta - r_t ) dt + ...
95
votes
5answers
243k views

How to break a long equation? [duplicate]

I have a long equation but long enough to occupy two lines. I want to break it to improve readability. How can I break it? \begin{equation} F = \{F_{x} \in F_{c} : (|S| > |C|) \cap (minPixels ...
56
votes
2answers
5k views

How do I number equations only if they are referred to in the text?

I have a paper where all equations are numbered, but I want to number equations only if they are actually referred to in the .tex file using \ref{}. How can I make that happen? Alternatively, how can ...
41
votes
5answers
7k views

How to write a perfect equation parameters description?

A symbols or parameters description is shown below, however, the = and the details of parameter are not aligned. I want to make a parameters list for a equation like this, in which symbols, = and ...
27
votes
3answers
5k views

How to make a standalone document with one equation?

I was surprised to find that standalone package can not compile a document with an equation: \documentclass{standalone} \begin{document} \begin{equation} % not working! F(V, T) = E(V) + D(T) ...
56
votes
3answers
66k views

align* but show one equation number at the end

I am using align*, but I still need an equation number. I know one solution is to use align and add \nonumber to all lines but the last. Is there a 'lazy' way to do it? I searched a little and found ...
38
votes
3answers
10k views

Centering \vdots in a system of many equations

I have a system of equations with an arbitrary number of equations (k). I'd like to use \vdots to compactly describe the system, like so: \begin{align*} R(-1) &= \sum_{i=1}^m A(i)R(i-1) \\ ...
10
votes
1answer
20k views

Left align (to the page) displayed math

How can I left align the display math environment (either $$ or \[)? I keep running into people asking about the align environment; but I just want to change displayed math from center to left align ...
47
votes
3answers
60k views

Label equation with a symbol

I would like to label an equation with an arbitrary symbol, rather than a number, or letter. Is this possible?
22
votes
2answers
18k views

How to globally change the spacing around equations?

How could I go about setting the 'above' and 'below' vspaces around the equation environment? If the same could be done for the subequations or gather environments, this would be a bonus.
21
votes
4answers
9k views

Making a new environment combining equation and split

I'm trying to define a new environment that consists of a split environment inside an equation environment. But I'm getting an error. Here's what I'm doing: \documentclass[a4paper,12pt]{article} ...
42
votes
3answers
4k views

Which command should I use for displayed equations?

A number of related questions have already been asked about this issue: align vs equation which is preferable to what to do with this hyperref note on amsmath and even eqnarray vs align But I'm ...
50
votes
4answers
89k views

How can I change the font size in math equations?

I find that whenever I'm typing some equations into a document, and the equation gets a bit complex (let's say a fraction in a parentheses, squared, inside a square root, inside a fraction), the ...
30
votes
2answers
21k views

Multi-page equations — problem

I have a very long derivation, that needs to look like: A = B \\ = C \\ = D \\ etc. The derivation spans across many lines. I'm looking for a way to typeset it so that when it reaches the end of ...
25
votes
4answers
6k views

Sharing alignment between equations in two different items

In the following minimal example, I have two equations inside an itemize environment, with an item per equations. Each equation is defined in its own equation environment. \documentclass{article} ...
34
votes
3answers
96k views

How to write a function (piecewise) with bracket outside?

How to write this Piecewise function using LaTeX? I tried $ \begin{array}{cc} \{ & \begin{array}{cc} 0 & x\leq 0 \\ \frac{100-x}{100} & 0\leq x\leq 100 \\ 0 ...
34
votes
6answers
6k views

For formal articles, should a displayed equation be followed by a punctuation to conform to the language grammar ?

For formal articles, should a displayed equation be followed by a punctuation to conform to the language grammar ? For example: The most well-known physics formula is \[E=mc^2.\] %should I put ...
38
votes
5answers
6k views

How can I get an underbrace and an overbrace to partially overlap in an equation?

Sometimes I want to describe portions of an equation using \underbrace and \overbrace in such a way that the portions are not completely distinct, for example: /-------\ x = A + B + C + D + E ...
19
votes
1answer
131k views

How to left align a set of equations.

I wanted to left align a set of equations. I've tried the solution provided in aligning to the left. It worked. But, I wanted to have a single equation number for the entire flalign in order to refer ...
13
votes
5answers
3k views

Help me to write Long LaTeX equations fast with colours and possibly with other aids

I am too slow LaTeX-typist, for example with the equations below I cannot find where I am missing some bracket. Could someone offer me some computational method? I use Vim but I am happy with any ...
40
votes
4answers
16k views

How can I get rid of indentation after an equation?

I'm a total newbie to LaTeX and I get very annoyed about this. Every time I write an equation, the text following the equation has some indentation but I don't want it to be there! Look at the ...
20
votes
2answers
8k views

Highlight an equation within an align environment

I would like to define a command that puts a red box around an equation with yellow highlighting. I have the basics working pretty well. What I am unable to figure out is: How to keep the alignment ...
19
votes
1answer
20k views

How can I add left aligned text to an equation?

I have a document I am trying to copy to learn TeX. Here is what I have encountered: How can I have the "or" in the equation. This is what I have right now: \[ f = ma; \] But $a$ is the change in ...
32
votes
5answers
3k views

LaTeX accessibility

Does anyone know of any LaTeX modules that makes the pdf output generated by pdflatex Americans with Disabilities Act of 1990 (ADA)/Section 508 compliant? Specifics: With regard to math. One simple ...
9
votes
2answers
1k views

custom automatic equation numbering

I just read a book where the equations in the Introduction were numbered slightly differently compared to the other sections, namely by (In.x) where x stands for the number (so it starts off as ...
11
votes
2answers
480 views

Equation number enclosing parentheses misplaced with Polyglossia+Hebrew+amsmath

I am compiling the following MWE using XeLatex within TeXnicCenter and get a garbled equation number: \documentclass{article} \usepackage{amsmath} \usepackage{polyglossia} \setmainlanguage{hebrew} ...
36
votes
4answers
75k views

Reducing font size in equation

I wanted to type an equation in LaTeX. But it is too long to fit into one line. It involves big arrays with many columns so I cannot split it. I wanted to reduce the font size so that it can fit in ...
34
votes
4answers
77k views

Attractive Boxed Equations

I often used \boxed{...} from the AMS math package to place a box around important equations. However, this approach often produces somewhat awkward looking output. Consider \documentclass{article} ...
69
votes
2answers
17k views

Two letter variable names

In math mode, TeX assumes "hidden multiplication" (so that two variable names put nearby have invisible multiplication between), so that, AFAICT, expressions like $ABC$ are rendered with small ...
50
votes
3answers
79k views

Show equation number only once in align environment

I want the equation number to be shown only at the last line, or better, somewhere in the middle of all. So instead of (1), (2), ... only (1). I use \begin{align} ... \end{align}
17
votes
6answers
6k views

Align two inequalities

I am trying to align two inequlities vertically. The \le signs should have the same horizontal positions and the term in the should be centered. My first attempt: \begin{align*} \sum a &\le \sum ...
20
votes
3answers
7k views

Alignment of equals sign in multiple align environments

I have multiple align environments in my document, separated by a small paragraph of text: \begin{align*} foo &= something very very long compared to the other align \end{align*} explanation ...
18
votes
4answers
651 views

Graphics equations: put text on equations

I have a big question that I cannot solve by myself. I would like to add text on my equations, but I like to have some graphics on those. For instance, I would like to explain why I am doing ...
15
votes
3answers
8k views

Aligning across 'aligned' equation blocks

I'd like to format two groups of equations such that all their equal signs line up and such that I can put a big brace to the right of each block to annotate that block. The last part is easily ...
17
votes
1answer
9k views

How to reference equations using letters and numbers

Sometimes it is convenient to refer to a group of equations by a letter and a number. For example: 2+1 (A1) 2+4 (A2) x^4 (B3) x^e (B4) Placing ...
10
votes
4answers
6k views

How to export a equation as a image without background?

For example, if we have a equation on a file like: \documentclass[12pt]{standalone} \usepackage{varwidth} \usepackage[utf8x]{inputenc} \usepackage[T1]{fontenc} \usepackage{amsmath, amssymb, ...
11
votes
4answers
8k views

abovedisplayskip vs abovedisplayshortskip

What is the difference between these two? http://en.wikibooks.org/wiki/TeX/abovedisplayskip http://en.wikibooks.org/wiki/TeX/abovedisplayshortskip I don't know why, but it seems to work unusually. ...
8
votes
2answers
1k views

Defining a new command for making functional lines / package

As you have probably guessed from the title my mother tounge is not English. Therefore I have no idea if "Functional lines" is the correct term for what I am looking for. Basically I am looking to ...
12
votes
1answer
3k views

Blank lines in align environment

Is there a way to insert a blank line between two equations in align environment? From what I understand a blank line is interpreted as \par and \par is not allowed in align. Can I disable this ...
10
votes
3answers
2k views

How can I number a few equations together

i would like to write few equations, but all the equations will get only once numbered and in the middle (right side) of the equations. e.q. if i write 3 equations, the number will be to the right of ...
6
votes
3answers
3k views

Errors in matrix equation?

I'm getting errors in a matrix equation. When I compile it looks fine, but I'd like to fix them so I don't have to press return for every error at compile time. The code for the equation is: ...