{math-mode} is about typesetting mathematical content, e.g. tweaking the appearance of spacing and symbols in a formula, or producing specific mathematical constructs. For questions about "wrapper" environments like equation or align, consider the tag {equations}.

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251
votes
8answers
21k 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 ...
161
votes
8answers
11k views

Are \( and \) preferable to dollar signs for math mode?

Along the lines of Why is \[ ... \] preferable to $$?, what reasons are there (if any) to favor \( ... \) over $ ... $?
132
votes
7answers
191k views

How can I get bold math symbols?

To make Latin-letter variables bold I can use e.g. \mathbf{a}, but while putting Greek letters or symbols such as \nabla inside \mathbf doesn't cause any errors or warnings, it also doesn't do ...
121
votes
4answers
92k views

What are all the font styles I can use in math mode?

As can be seen in above picture, there are lots of fonts or font styles that can be used in math mode. What are all the fonts or font styles I can use in math mode, and which packages are required ...
89
votes
8answers
25k views

How to typeset $:=$ correctly?

I like to use $:=$ for "is defined to be equal to", but this is never typeset with the symmetry one would like, as the colon is always too low relatively to the equals sign. Is there any way of ...
79
votes
4answers
52k views

\mid, | (vertical bar), \vert, \lvert, \rvert, \divides

What's the difference between the different vertical bars? $S = \{\, x \mid x \not= 17 \,\}$ $a \vert b$ implies $a \leq b$ when $b \ne 0$ $a|b$ implies $a \leq b$ when $b \ne 0$ $\lvert x \rvert$ is ...
78
votes
3answers
172k views

Absolute Value Symbols

What is the "best LaTeX practices" for writing absolute value symbols? Are there any packages which provide good methods? Some options include |x| and \mid x \mid, but I'm not sure which is best...
76
votes
12answers
61k views

What is the best symbol for vector/matrix transpose?

What is the best or most popular symbol for vector/matrix transpose? I have used simply ^T, for example $c^T x$. I think it is ugly, mainly because it is a little too big compared with vector ...
76
votes
3answers
28k views

What's the difference between \mathrm and \operatorname?

I apparently can't see the difference in a compilation (pdflatex) between \mathrm and \operatorname. So, as in the title the question is: is there a difference? Which one is preferable in what ...
76
votes
4answers
4k views

Spacing around \left and \right

Why does the addition of a \left and \right introduces an extra space around the formula? Specifically, why do $\cos(\theta)$ and $\cos\left(\theta\right)$ render differently? Is there a way to use ...
76
votes
3answers
76k views

What is the “correct” way of embedding text into math mode?

Lets say I have something like: \[ Let x = number of cats \] (This is a contrived example, but pretend we are actually inside a long align environment block...) "Let" and "number of cats" need to ...
75
votes
4answers
148k 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)} ...
75
votes
4answers
85k views

Command for argmin or argmax?

How can you get the argmin or argmax in Latex? Two solutions I found are: \underset{x}{\operatorname{argmax}} \DeclareMathOperator*{\argmin}{arg\,min} Any other ideas? [1] ...
68
votes
5answers
1k views

{(x+y)}^2 or (x+y)^2?

This expression is just an example, of course. My question is: should one always specify the quantity being exponentiated by surrounding it with braces, or is it acceptable to drop those braces? ...
67
votes
4answers
67k views

“(” or “\left(” parentheses?

What is the difference between ( and \left( in LaTeX? Sometimes, when the content is small, it does not seem to matter which pair I use. What is the best practice when it comes to which parentheses ...
63
votes
4answers
11k 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 ...
63
votes
4answers
15k views

When not to use \ensuremath for math macro?

I have gotten into the habit of using \ensuremath around math components in every macro that I define, so that I can use the same macro inside and outside of math mode. But egreg's comments in ...
62
votes
2answers
12k 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 ...
61
votes
5answers
114k views

How to add a matrix to a LaTeX document

How do we add a matrix to a LaTeX document?
59
votes
2answers
14k views

Using \colon or : in formulas?

I noticed that in many documents you encounter $f: X \to Y$ instead of $f \colon X \to Y$. Another example are quantified expressions: $\forall x: P (x)$ versus $\forall x \colon P(x)$. I find the ...
58
votes
2answers
69k views

Nice looking empty set?

I feel like the standard $\emptyset$ is ugly. By hand, my empty set symbol is a lot rounder, then this "slashed-zero"-type symbol. Two questions: Do people really use it (I mean people who have any ...
56
votes
2answers
67k views

How can I get text underneath an underbrace?

I am looking to do something of the following: To get text underneath the underbrace. Is it involving \stackrel or some sort of similar command?
56
votes
3answers
18k views

Allowing line break at ',' in inline math mode?

In the inline math mode ($...$), if the formula is too long, LaTeX will try to break it on operators, e.g. very long text followed by a very long equation like $a+b+c+d+e+f+g+h+i+j+k+l$ etc may be ...
55
votes
6answers
20k views

Prevent LaTeX to break an inline math equation

I hope this question was not asked before. At least I haven't found it. I have an inline math equation and LaTeX is breaking it into two parts. In this case I'd prefer to have the whole and short ...
54
votes
2answers
8k views

automatic size adjustment for nested parentheses

As I prefer outer parentheses to grow larger in nested expressions, I happen to insert \bigl and \bigr and its larger cousins a lot. I have always wondered whether there is a way to do this ...
52
votes
3answers
188k views

Big Parenthesis in an Equation

I have an equation contained inside \[...\], which automatically makes a \sum with sub- and superscripts turn big--so that the summation sign looks awkward inside parenthesis. Any idea how to make ...
52
votes
6answers
21k views

How can I write multiple lines in a subscript?

Is there a way to force a line break inside a math mode text? My example: \[ \underbrace{....}_\text{Some long text that should be multiline} \] Trying \text{Some long text that\\ should be ...
50
votes
9answers
5k views

LaTeX/Math jokes [closed]

Lighten up a bit guys. How about the following \documentclass{article} \usepackage{graphicx} \begin{document} If~~$\displaystyle\lim_{x\rightarrow8}\frac{1}{x{-}8}=\infty$ ...
50
votes
2answers
18k views

How to get Beamer Math to look like Article Math

In a LaTeX article, the math characters are more "curvy" than the text characters: \documentclass[12pt]{article} \begin{document} $x^2 + y^2 = z^2$ \end{document} In a beamer presentation, the ...
50
votes
5answers
11k views

Should I \mathrm the d in my integrals?

When writing an integral, it seems like something should be done to separate the "d", as in \int f(x) dx, so as not to confuse it with a variable. I've seen it left as-is, bolded, and straightened. ...
49
votes
4answers
2k views

How do I display pi in LaTeX like Don?

Way back in 1979, Donald Knuth, tried to give the feeling that π is irrational using the idea of infinite sequence of smaller and smaller font sizes like what I have tried to do here using HTML and ...
48
votes
8answers
12k views

Highlight elements in the matrix

I have a matrix and need to highlight some elements in the matrix. I have found how to highlight a single element (I want to put the cell in the square): $$ A = \begin{bmatrix} \fbox{0} & ...
47
votes
4answers
42k views

Show inline math as if it were display math

I'm very familiar with how symbols display differently in inline mode (with $) vs. how display math shows them (with \[ or $$). Two examples would be with limits $\lim_{n\righarrow \infty}f(x)$ ...
47
votes
2answers
7k views

What is the advantage of using $f^\prime$ instead of $f'$?

Although the two outputs look quite similar, what is the advantage of using $f^\prime$ instead of $f'$? By the way, here is my code: \documentclass‎{article‎}‎ \begin{document}‎‎‎ \[‎ ‎f^‎\prime ...
46
votes
1answer
490 views

Is it always best practice to not include text punctuation in inline math mode?

It has been pointed out on this site, e.g. here by egreg, that text punctuation doesn't belong to the formula in inline math. I've been following this practice for a long time, so I write for all ...
45
votes
1answer
73k views

\mathbb{Z} yields undefined control sequence error

I am using WinEdt 6 for compiling my TeX documents. I am getting an error with contains the line $\mathbb{Z}$ showing that it is undefined control sequence. How should I rectify it? Should I include ...
44
votes
6answers
4k views

Writing readable LaTeX

Lets say I have the following LaTeX code \subsection{Convex sets} A set \( \mathcal{S} \) in \( \mathbb{R}^n \) is said to be convex if \[ \mathbf{x}_1, \mathbf{x}_2 \in \mathcal{S} \implies \lambda ...
44
votes
6answers
11k views

Define additional math operators to be typeset in roman

Mathematical operators, such as function names, should be set in roman type, not italics. Latex already has commands for some operators, including \max, \min, and \log. How can I define additional ...
44
votes
4answers
25k views

When one should use spacing line \quad or \,

In general, in most places, it is said that using TeX defaults is the best. However, TeX does provide things like \, and \quad etc. When one should use them? Both in general and in math mode in ...
43
votes
1answer
37k views

How to add extra spaces between rows in tabular environment?

I couldn't find any option that lets me expand the vertical space between rows in tabular environment. For example, \begin{tabular}{c c} $f^{(n)}(x)$ & $f^{(n)}(0)$ \\ ...
42
votes
7answers
4k views

\subseteq + \circ as a single symbol (“open subset”)

I'm trying to create symbols \opn for "open subset" and \cls "closed subset". I want them to look like this: My current solution is: ...
42
votes
2answers
9k views

“Closed” (square) root symbol

I found a cool trick in the LaTeX wikibook which allows the square root sign to be altered such that it "closes" over its contents. Here's an example: ("closed" root on the left, normal one on the ...
41
votes
7answers
4k views

Automatic left and right commands

Is it possible to automatically "add" \left and \right commands in front of all brackets? The source code should be left intact, but LaTeX should interpret every pair of brackets as if they were ...
41
votes
2answers
18k 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}} ...
41
votes
2answers
22k views

Vertical Spacing within align environment accounting for fractions

The default vertical spacing within an align environment seems very tight when there are fractions in the lines. I am aware of three manual tweaks that can be applied: Adjust the value \jot. ...
40
votes
4answers
52k views

Math symbol question: Vertical bar for ''evaluated at …''

How do I insert the line "|" after the equation in LaTeX (see image below)? I'm using LyX so if you can point me to the symbol of that line is also OK. I don't know if this line has a proper name ...
40
votes
4answers
68k 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 ...
40
votes
3answers
51k views

How to add text under symbol in equation ?

I was trying to make something like this (something similar to \substack in \sum) in equation. How to do this ?
39
votes
4answers
2k views

What is the Necessity of $…$ Around Numbers?

I typed up an assignment with a lot of numbers in LaTeX and turned it in to my adviser. When he returned it to me with some corrections, one of which was a lot of $ around my numbers. I understand ...
39
votes
6answers
8k views

Best way to create an system of equations environment?

I am trying to write a few systems of equations, and I want the terms to be nicely spaced as below 2x + y + 3z = 10 \\ x + y + z = 6 \\ x + 3y + 2z = 13 Now, using ...