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Questions tagged [equations]

{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.

519
votes
8answers
102k 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 ...
212
votes
6answers
605k views

How can I split an equation over two (or more) 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)} ...
179
votes
5answers
377k 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 ...
174
votes
2answers
9k 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}x ...
169
votes
5answers
554k 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 &...
148
votes
4answers
202k 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}
145
votes
5answers
91k 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 ...
131
votes
2answers
214k 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?
121
votes
3answers
128k 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 ...
118
votes
3answers
67k 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 ...
115
votes
4answers
88k 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 + \...
114
votes
4answers
368k 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 &...
107
votes
7answers
363k 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{...
101
votes
2answers
68k 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(...
97
votes
2answers
32k 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 ...
87
votes
3answers
146k 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?
87
votes
4answers
186k 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} ...
79
votes
7answers
270k 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 ...
75
votes
5answers
42k 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?
71
votes
2answers
11k 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 ...
70
votes
5answers
224k 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 ...
69
votes
6answers
26k 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 ...
66
votes
3answers
142k views

Symbol for Gaussian distribution

What is the symbol for the normal density function in LaTeX?
63
votes
4answers
116k 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 ...
62
votes
6answers
32k views

How to write a perfect equation parameters description?

Equation's symbols or parameters description are 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,...
61
votes
3answers
317k views

How to write partial differential equation (Ex. dQ/dt=ds/dt) with real partial derivative signs?

I would like to make a partial differential equation by using the following notation: dQ/dt (without / but with a real numerator and denomenator). Earlier today I got help from this page on how to ...
61
votes
3answers
25k 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{...
59
votes
2answers
262k 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(\...
59
votes
4answers
29k 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 ...
57
votes
1answer
209k views

Left brace including several lines in eqnarray [duplicate]

How is it possible to make a brace and have something like this in a eqnarray block?
52
votes
4answers
228k views

Why \\ does not go to new line in equation?

\begin{equation*}\label{eq:pareto mle2} A_0 = \frac{1}{(\alpha+t_x)^{r+s+x}}{}_2F_1\left(r+s+x,x+1;r+s+x+1;\frac{\alpha-\beta}{\alpha + t_x} \right ) "\\\" <br> - \frac{1}{(\alpha+T)^{r+s+x}}{}...
50
votes
2answers
207k views

Write 'text' **correctly** in equations

Although many have attempted to explain the difference among \mathrm, \textrm, \textnormal and \text (and others?), I found them misleading. See for example the LaTeX's Wiki \mathrm explanation Why ...
48
votes
3answers
24k 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(-...
47
votes
2answers
38k 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.
47
votes
6answers
11k 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 ...
46
votes
2answers
34k 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 ...
44
votes
5answers
303k views

Align equation left

Here is my split equation: \documentclass{article} \usepackage{amsmath} \begin{document} \begin{equation} \begin{split} a_{ijk} =& \frac {Pr(M_{I} =2 \& M_J=1 \& M_K =1 | I=i , J=j , K=...
43
votes
1answer
67k views

What is the difference between \eqref and \ref?

Is there any difference between \eqref and \ref? I used both of them in my document using the package classicthesis and saw no difference in the result. Is there any specific situation in which I ...
43
votes
4answers
110k 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]{...
42
votes
11answers
19k 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?
42
votes
3answers
7k 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
36k 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 ...
41
votes
2answers
51k views

add vertical space between equations

I am using the following code to combine two equations with one number in parentheses but the two equations are very close to each other and using '\vspace{} not working How can i add a vertical ...
41
votes
1answer
12k 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
1answer
26k views

Is there a standard way to refer to a range of equations?

I have occasionally wanted to refer to a range of equations in my document. So far, I've been using Equations~\eqref{firstEquation}~--~\eqref{lastEquation}, which produces something like "Equations (...
39
votes
4answers
13k 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} \...
38
votes
3answers
54k 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{...
37
votes
3answers
19k 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 ...
37
votes
2answers
14k views

Aligned equations inside of TikZ node.

How can I create a tree node with an aligned math equations inside? \begin{align} \end{align} doesn't work \begin{minipage}{100} \begin{align} ... \end{align} \end{minipage} Gives a lot of ...
35
votes
2answers
114k views

Align multiline equation with expression after equal sign

I am trying to align a multiline equation using array within the equation but it turns out it doesn't do very well. The code I am using is as follows: \begin{equation} \begin{array}{lcl} \mathcal{...