{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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328
votes
8answers
34k 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 ...
149
votes
1answer
5k views

Making equations copyable in pdf

I would like to write a .pdf, where my readers could copy the rendered formulae and paste them directly in their TeX documents. And the copied text would automatically be: \int x\sin ax\;\mathrm{d}...
125
votes
5answers
191k 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 ...
117
votes
5answers
257k 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)} ...
102
votes
5answers
261k 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 &...
89
votes
4answers
24k 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 ...
75
votes
2answers
89k 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?
73
votes
2answers
18k 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 ...
70
votes
3answers
38k 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 + \...
62
votes
3answers
71k 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 ...
61
votes
2answers
33k 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}} f(...
60
votes
3answers
86k 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}
57
votes
2answers
6k 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 ...
54
votes
6answers
178k views

How do I turn off equation auto numbering

I have an equation like this: \begin{align} P(A \cup B) = \sum_{\omega \in A \cup B} P(\omega) = \sum_{\omega \in A} P(\omega) + \sum_{\omega \in B} P(\omega) = P(A) + P(B) \end{...
53
votes
4answers
92k 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 ...
53
votes
1answer
29k views

Is it possible to pagebreak aligned equations?

The report I'm writting features a lot of long, multiple lines equations. To reduce visual polution I've been using an aligned environment nested inside equation. This way (unlike just using an align ...
52
votes
4answers
12k 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?
50
votes
3answers
63k 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?
42
votes
5answers
8k 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 ...
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 ...
42
votes
1answer
8k views

Breaking equations with breqn

I am new to using the breqn package. It looks good, but I get an odd behaviour when an equation can almost fit in the page but not quite: the alignment gets completely wrong. Is there a way to fix ...
40
votes
2answers
139k views

How do you center equations?

I can't seem to center equations without causing some weird formatting problem. The following results in the R being dropped: \begin{center} E(R_{i,t})=E(\alpha_i)+E(\beta_{i,F_1 } F_{1,t})+E(\...
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 ...
39
votes
6answers
96k views

How to align a set of multiline equations

I am trying to align a set of long equations, that are themselves align environments as most of them are spreading on multiple lines. Currently I just have a sequence of align environments, with ...
38
votes
3answers
11k 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) \\ R(-...
38
votes
4answers
83k 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 ...
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 ...
38
votes
4answers
82k 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} ...
37
votes
11answers
10k views

Embedding LaTeX equations into a webpage

I'd like to include some basic math equations into a webpage. Is there an easy way of either compiling the LaTeX into an image which I can upload, or else of having the browser parse the code?
36
votes
3answers
106k 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 &...
36
votes
1answer
56k views

Symbol for Gaussian distribution

What is the symbol for the normal density function in LaTeX?
35
votes
6answers
7k 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 ...
32
votes
3answers
40k views

Adding letters to equation numbers

I want to number use a equation and add a letter to the equation number such as: f(x) =a x and g(x) = b x (3.1.1a,b) That is e.g. using \begin{equation} ... \label{eq} \end{...
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 ...
31
votes
2answers
22k 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 ...
31
votes
2answers
932 views

Equation connected by lines

I have written a code that defines a new environment in which aligned equation are connected by lines as in the image: I think it is useful when, inside the align environment, there is the need of ...
30
votes
3answers
6k 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) \end{...
29
votes
6answers
5k views

How to make an equation more compact?

I have an equation that wastes a lot of space around the union symbol: \documentclass{article} \usepackage[cmex10]{amsmath} \usepackage{amssymb} \begin{document} \begin{equation} RA_U \left ( new ,...
29
votes
4answers
64k views

Aligned equations in LaTeX

I have a long equation in LaTeX, which I need to break up into more lines. I've done this, although its not quite what I was looking for. Here is a MWE showing my problem: \documentclass[10pt]{...
27
votes
3answers
3k views

Getting a tikz picture to have an equation number

I make a lot of commutative diagrams and am trying to switch to Tikz from amcd,diagrams, etc. I often have to refer to these diagrams in the text and would rather have them as equations (i.e. with and ...
26
votes
9answers
1k views

Best typesetting of formula

Consider the following example. \documentclass{article} \usepackage{amsmath} \newcommand*\mathsetfont{\mathbf} \newcommand*\DeclareMathSet[1]{% \expandafter\newcommand\csname set#1\endcsname{\...
26
votes
3answers
10k views

Guidelines for typesetting fractions

I realize that this question is to some extent subjective. However, I suspect that there are some common standards regarding how fractions ought to be typeset in mathematics. The guide Mathematical ...
26
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} \...
25
votes
1answer
21k views

Placing equation numbers on the right

I am new to TeX and am using scribtex to write a maths paper. When I put the followng code, the equation number is automatically displayed on the left, instead of in the right as is usually done. What ...
25
votes
1answer
18k views

Multiple Alignment in equations

The following equations need to be aligned in two spots. If I use the align* environment then the second column of alignment is pushed to the right edge of the page. I googled this and saw that ...
25
votes
2answers
4k views

Should one use thousands separators in equations?

I understand that this is not strictly a TeX question but I have recently been asked to correct an equation presented as the first example in the image below to that of the second example i.e., to use ...
25
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 ...
25
votes
3answers
1k views

How to avoid widow lines after displayed equations

If a displayed equation is close to the bottom of the page, TeX likes to insert a page break even if the current paragraph contains only one more line after the equation, as e.g. in ... it follows ...
24
votes
6answers
1k views

Is there a way to format the equation like this?

My friend is taking pre-calculus class, and I would like to create some notes for him. Is there a way I can do the following in latex? Right now I only have the very basic down. I want to make it ...
24
votes
2answers
2k views

Why does no one fix eqnarray?

It seems to me that everyone agrees that no one should use the latex built-in eqnarray environment. So much so that packages have been made to fix it, and several alternatives have been made, ie. ...