Help:Displaying a formula

Revision as of 14:29, 20 April 2023 by Caleb Cooper (talk | contribs)
This content is in the Help Namespace.
This screenshot shows the formula E = mc2 being edited using VisualEditor. The visual editor shows a button that allows to choose one of three offered modes to display a formula.

There are three methods for displaying formulas in Wikipedia: raw HTML, HTML with math templates (abbreviated here as {{math}}), and a subset of LaTeX implemented with the HTML markup <math></math> (referred to as LaTeX in this article). Each method has some advantages and some disadvantages, which have evolved over the time with improvements of MediaWiki. The manual of style for math has not always evolved accordingly. So the how-to recommendations that appear below may differ from those of the manual of style.

For example, the famous Einstein formula can be entered in raw HTML as {{nowrap|''E'' {{=}} ''mc''<sup>2</sup>}}, which is rendered as E = mc2 (the template {{nowrap}} is here only for avoiding a line break inside the formula). With {{math}}, it can be entered as {{math|''E'' {{=}} ''mc''{{sup|2}}}}, which is rendered as E = mc2. With LaTeX, it is entered as <math>E=mc^2</math>, and rendered as .

Use of raw HTML

Variable names and many symbols look very different with raw HTML and the other display methods. This may be confusing in the common case where several methods are used in the same article. Moreover, mathematicians who are used to reading and writing texts written with LaTeX often find the raw HTML rendering awful.

So, raw HTML should normally not be used for new content. However, raw HTML is still present in many mathematical articles. It is generally a good practice to convert it to {{math}} format, but coherency must be respected; that is, such a conversion must be done in a whole article, or at least in a whole section. Moreover, such a conversion must be identified as such in the edit summary, and it should be avoided making other changes in the same edit. This is for helping other users to identify changes that are possibly controversial (the "diff" of a conversion may be very large, and may hide other changes).

Converting raw HTML to {{math}} is rather simple: when the formula is enclosed with {{nowrap}}, it suffices to change "nowrap" into "math". However, if the formula contains an equal sign, one has to add 1= just before the formula for avoiding confusion with the template syntax; for example, {{math|1=''E'' = ''mc''{{sup|2}}}}. Also, vertical bars, if any, must either be replaced with {{!}} or avoided by using {{abs}}.

LaTeX vs. {{math}}

These two ways of writing mathematical formulas each have their advantages and disadvantages. They are both accepted by the manual of style. The rendering of variable names is very similar. So having a variable name displayed in the same paragraph with {{math}} and <math> is generally not a problem.

The disadvantages of LaTeX are the following: On some browser configurations, LaTeX inline formulas appear with a slight vertical misalignment, or with a font size that is slightly different from that of the surrounding text. This is not a problem with a block displayed formula. This is generally also not a real problem with inline formulas that exceed the normal line height (for example formulas with subscripts and superscripts). Also, the use of LaTeX in a piped link or in a section heading should appear in blue in the linked text or the table of content, but they do not. Moreover, links to section headings containing LaTeX formulas do not work always as expected. Finally, too many LaTeX formulas may significantly increase the processing time of a page. LaTeX formulas should be avoided in image captions, because when the image is clicked for a larger display, LaTeX in the caption will not render.

The disadvantages of {{math}} are the following: not all formulas can be displayed. While it is possible to render a complicated formula with {{math}}, it is often poorly rendered. Except for the most common ones, the rendering of non-alphanumeric Unicode symbols is often very poor and may depend on the browser configuration (misalignment, wrong size, ...). The spaces inside formulas are not managed automatically, and thus need some expertise for being rendered correctly. Except for short formulas, many more characters have to be typed for entering a formula, and the source is more difficult to read.

Therefore, the common practice of most members of WikiProject mathematics is the following:

  • Use of {{mvar}} and {{math}} for isolated variables and very simple inline formulas
  • Use of {{mvar}} and {{math}} for formulas in image captions, even if the rendering is mediocre
  • Use of LaTeX for displayed formulas and more complicated inline formulas
  • Use of LaTeX for formulas involving symbols that are not regularly rendered in Unicode (see wikipedia:MOS:BBB)
  • Avoid formulas in section headings, and when this is a problem, use raw HTML (see Finite field for an example)

The choice between {{math}} and LaTeX depends on the editor. So converting from a format to another one must be done with stronger reasons than editor preference.

Display format of LaTeX

By default SVG images with non-visible MathML are generated. The text-only form of the LaTeX can be set via user preferences at My Preferences – Appearance – Math.

The hidden MathML can be used by screen readers and other assistive technology. To display the MathML in Firefox:

In either case, you must have fonts that support MathML (see developer.mozilla.org) installed on your system. For copy-paste support in Firefox, you can also install MathML Copy.

Use of HTML templates

TeX markup is not the only way to render mathematical formulas. For simple inline formulas, the template {{math}} and its associated templates are often preferred. The following comparison table shows that similar results can be achieved with the two methods. See also Help:Special characters.

TeX syntax TeX rendering   HTML syntax HTML rendering
<math>\alpha</math>   {{math|''&alpha;''}}   or   {{mvar|&alpha;}} α   or   α
<math>f(x) = x^2</math>   {{math|''f''(''x'') {{=}} ''x''<sup>2</sup>}} f(x) = x2
<math>\{1,e,\pi\}</math>   {{math|{{mset|1, ''e'', ''&pi;''}}}} {1, e, π}
<math>|z + 1| \leq 2</math>   {{math|{{abs|''z'' + 1}} &le; 2}} z + 1| ≤ 2

HTML entities

Though Unicode characters are generally preferred, sometimes HTML entities are needed to avoid problems with wiki syntax or confusion with other characters:

< > ·
&lt; &gt; &minus; &bull; &prime; &Prime; &sdot; &middot; &ndash; &mdash;

In the table below, the codes on the left produce the symbols on the right, but these symbols can also be entered directly in the wikitext either by typing them if they are available on the keyboard, by copy-pasting them, or by using menus below the edit windows. (When editing any Wikipedia page in a desktop web browser, use the "Insert" pulldown menu immediately below the article text, or the "Special characters" menu immediately above the article text.) Normally, lowercase Greek letters should be entered in italics, that is, enclosed between two single quotes ('').

HTML syntax Rendering
&alpha; &beta; &gamma; &delta; &epsilon; &zeta;
&eta; &theta; &iota; &kappa; &lambda; &mu; &nu;
&xi; &omicron; &pi; &rho; &sigma; &sigmaf;
&tau; &upsilon; &phi; &chi; &psi; &omega;

α β γ δ ε ζ
η θ ι κ λ μ ν
ξ ο π ρ σ ς
τ υ φ χ ψ ω

&Gamma; &Delta; &Theta; &Lambda; &Xi; &Pi;
&Sigma; &Phi; &Psi; &Omega;

Γ Δ Θ Λ Ξ Π
Σ Φ Ψ Ω

&int; &sum; &prod; &minus; &plusmn; &infin;
&asymp; &prop; = &equiv; &ne; &le; &ge;
&times; &middot; &sdot; &divide; &part; &prime; &Prime;
&nabla; &permil; &deg; &there4; &empty;

∫ ∑ ∏ − ± ∞
≈ ∝ = ≡ ≠ ≤ ≥
× · ⋅ ÷ ∂ ′ ″
∇ ‰ ° ∴ ∅

&isin; &notin; &cap; &cup; &sub; &sup; &sube; &supe;
&not; &and; &or; &exist; &forall;
&rArr; &hArr; &rarr; &harr; &uarr; &darr;
&alefsym; - &ndash; &mdash;

∈ ∉ ∩ ∪ ⊂ ⊃ ⊆ ⊇
¬ ∧ ∨ ∃ ∀
⇒ ⇔ → ↔ ↑ ↓
ℵ - – —

Superscripts and subscripts

x2 x3 x2
1
x<sup>2</sup>x<sub>3</sub>x{{su|p=2|b=1}}

Spacing

To avoid line-wrapping in the middle of a formula, use {{math}}. If necessary, a non-breaking space ( ) can be inserted with "&nbsp;".

Typically whitespace should be a regular space ( ) or none at all. In rare circumstances, such as where one character overlaps another due to one being in italics, a thin space can be added with {{thin space}}.

Fractions

Fractions sometimes occur in regular text, and need proper presentation. Only a limited number are covered in the UTF-8 repertoire: they are ¼ ½ ¾ ⅓ ⅔ ⅕ ⅖ ⅗ ⅘ ⅙ ⅚ ⅛ ⅜ ⅝ ⅞

A number of these fractions have been added to the characters bar at the bottom of the edit page. The remainder have been left off since they do not render in the font used for Wikisource. They will appear here if your computer has Lucida Sans Unicode. They are overlarge compared with the regular font size.

Other fractions can be done with keyboard figures (like 11/16, 27/32, et cetera), but they are intrusive, being overlarge. More elegant fractions can be made by HTML coding, such as using the superscript/subscript markup.

Thus, 11/16 will be displayed by <span style="vertical-align:super;font-size:x-small">11</span>/<span style="vertical-align:sub;font-size:x-small">16</span>

Template:frac will produce 1116;

{{fs70|{{frac|11|16}}}} fits inline: 1116

Template:sfrac will produce vertical fractions fitting in with the Mediawiki typeface. Ex. 4 3/4, 67/83726;

{{fs70|{{sfrac|4|3}}}} fits inline: 4/3

Fractions can also be made with the TeX, but they do not match the Mediawiki typeface.

Functions

Functions are rendered in EMEA Support Wiki's by TeX using Mathoid. The text here is from the following sources:

General

Spaces and newlines are mostly ignored. Apart from function and operator names, as is customary in mathematics for variables, letters are in italics; digits are not. For other text, (like variable labels) to avoid being rendered in italics like variables, use \mbox or \mathrm: <math>\mbox{abc}</math> gives  

Line breaks help keep the wikitext clear, for instance, a line break after each term or matrix row.

Size

There are some possibilities, to change the size of the formulas. For example, fractions can be made smaller using \tfrac instead of \frac.

  becomes  .

In general, formulas can be made even smaller if \scriptstyle is employed:

  becomes  .

Special characters

Markup
 
 
Renders as <math>\text {abcdefghijklmnopqrstuvwxyzàáâãäåæçčďèéěêëìíîïňñòóôõöřšť÷øùúůûüýÿž}</math>

<math>\text {abcdefghijklmnopqrstuvwxyzàáâãäåæçčèéêëìíîïñòóôõö÷øùúûüýÿ}\,</math>


Or, using \mbox instead of \text, pretty much the same:

Markup
 
 
Renders as <math>\mbox {abcdefghijklmnopqrstuvwxyzàáâãäåæçčďèéěêëìíîïňñòóôõöřšť÷øùúůûüýÿž}</math>

<math>\mbox {abcdefghijklmnopqrstuvwxyzàáâãäåæçčèéêëìíîïñòóôõö÷øùúûüýÿ}\,</math>


But \mbox{ð} and \mbox{þ}:     Using \text{}    

For producing special characters without math tags, see Special characters.

Comparison: &alpha; gives "α" <math>\alpha</math> gives  , ("&" and ";" vs. "\", in this case the same code word "alpha"); &radic;2 gives "√2" <math>\sqrt{2}</math> gives   (the same difference as above, but also another code word, "radic" vs. "sqrt"; in TeX braces); &radic;(1-''e''&sup2;) gives √(1-e²), <math>\sqrt{1-e^2}</math> gives  , (parentheses vs. braces, "''e''" vs. "e", "&sup2;" vs. "^2").

The following symbols are reserved characters that either have a special meaning under LaTeX or are unavailable in all the fonts.

# $ % ^ & _ { } ~ \

Some of these can be entered with a backslash in front:

<math>\# \$ \% \& \_ \{ \} </math> gives  

Others have special names:

<math> \hat{} \quad \tilde{} \quad \backslash </math> gives  

Functions, symbols, special characters

Accents & diacritics

\dot{a}, \ddot{a}, \acute{a}, \grave{a}  
\check{a}, \breve{a}, \tilde{a}, \bar{a}  
\hat{a}, \widehat{a}, \vec{a}  

Standard numerical functions

\exp_a b = a^b, \exp b = e^b, 10^m  
\ln c, \lg d = \log e, \log_{10} f  
\sin a, \cos b, \tan c, \cot d, \sec e, \csc f  
\arcsin h, \arccos i, \arctan j  
\sinh k, \cosh l, \tanh m, \coth n  
\operatorname{sh}\,k, \operatorname{ch}\,l, \operatorname{th}\,m, \operatorname{coth}\,n  
\operatorname{argsh}\,o, \operatorname{argch}\,p, \operatorname{argth}\,q  
\sgn r, \left\vert s \right\vert  
\min(x,y), \max(x,y)  

Bounds

\min x, \max y, \inf s, \sup t  
\lim u, \liminf v, \limsup w  
\dim p, \deg q, \det m, \ker\phi  

Projections

\Pr j, \hom l, \lVert z \rVert, \arg z  

Differentials and derivatives

dt, \operatorname{d}\!t, \partial t, \nabla\psi  
dy/dx, \operatorname{d}\!y/\operatorname{d}\!x, {dy \over dx}, {\operatorname{d}\!y\over\operatorname{d}\!x}, {\partial^2\over\partial x_1\partial x_2}y  
\prime, \backprime, f^\prime, f', f'', f^{(3)}, \dot y, \ddot y  

Letter-like symbols or constants

\infty, \aleph, \complement, \backepsilon, \eth, \Finv, \hbar  
\Im, \imath, \jmath, \Bbbk, \ell, \mho, \wp, \Re, \circledS  

Modular arithmetic

s_k \equiv 0 \pmod{m}  
a\,\bmod\,b  
\gcd(m, n), \operatorname{lcm}(m, n)  
\mid, \nmid, \shortmid, \nshortmid  

Radicals

\surd, \sqrt{2}, \sqrt[n]{}, \sqrt[3]{x^3+y^3 \over 2}  

Operators

+, -, \pm, \mp, \dotplus  
\times, \div, \divideontimes, /, \backslash  
\cdot, * \ast, \star, \circ, \bullet  
\boxplus, \boxminus, \boxtimes, \boxdot  
\oplus, \ominus, \otimes, \oslash, \odot  
\circleddash, \circledcirc, \circledast  
\bigoplus, \bigotimes, \bigodot  

Sets

\{ \}, \O \empty \emptyset, \varnothing  
\in, \notin \not\in, \ni, \not\ni  
\cap, \Cap, \sqcap, \bigcap  
\cup, \Cup, \sqcup, \bigcup, \bigsqcup, \uplus, \biguplus  
\setminus, \smallsetminus, \times  
\subset, \Subset, \sqsubset  
\supset, \Supset, \sqsupset  
\subseteq, \nsubseteq, \subsetneq, \varsubsetneq, \sqsubseteq  
\supseteq, \nsupseteq, \supsetneq, \varsupsetneq, \sqsupseteq  
\subseteqq, \nsubseteqq, \subsetneqq, \varsubsetneqq  
\supseteqq, \nsupseteqq, \supsetneqq, \varsupsetneqq  

Relations

=, \ne, \neq, \equiv, \not\equiv  
\doteq, \doteqdot, \overset{\underset{\mathrm{def}}{}}{=}, :=  
\sim, \nsim, \backsim, \thicksim, \simeq, \backsimeq, \eqsim, \cong, \ncong  
\approx, \thickapprox, \approxeq, \asymp, \propto, \varpropto  
<, \nless, \ll, \not\ll, \lll, \not\lll, \lessdot  
>, \ngtr, \gg, \not\gg, \ggg, \not\ggg, \gtrdot  
\le, \leq, \lneq, \leqq, \nleq, \nleqq, \lneqq, \lvertneqq  
\ge, \geq, \gneq, \geqq, \ngeq, \ngeqq, \gneqq, \gvertneqq  
\lessgtr, \lesseqgtr, \lesseqqgtr, \gtrless, \gtreqless, \gtreqqless  
\leqslant, \nleqslant, \eqslantless  
\geqslant, \ngeqslant, \eqslantgtr  
\lesssim, \lnsim, \lessapprox, \lnapprox  
\gtrsim, \gnsim, \gtrapprox, \gnapprox  
\prec, \nprec, \preceq, \npreceq, \precneqq  
\succ, \nsucc, \succeq, \nsucceq, \succneqq  
\preccurlyeq, \curlyeqprec  
\succcurlyeq, \curlyeqsucc  
\precsim, \precnsim, \precapprox, \precnapprox  
\succsim, \succnsim, \succapprox, \succnapprox  

Geometric

\parallel, \nparallel, \shortparallel, \nshortparallel  
\perp, \angle, \sphericalangle, \measuredangle, 45^\circ  
\Box, \blacksquare, \diamond, \Diamond \lozenge, \blacklozenge, \bigstar  
\bigcirc, \triangle, \bigtriangleup, \bigtriangledown  
\vartriangle, \triangledown  
\blacktriangle, \blacktriangledown, \blacktriangleleft, \blacktriangleright  

Logic

\forall, \exists, \nexists  
\therefore, \because, \And  
\or \lor \vee, \curlyvee, \bigvee  
\and \land \wedge, \curlywedge, \bigwedge  
\bar{q}, \bar{abc}, \overline{q}, \overline{abc},

\lnot \neg, \not\operatorname{R}, \bot, \top

 

 

\vdash \dashv, \vDash, \Vdash, \models  
\Vvdash \nvdash \nVdash \nvDash \nVDash  
\ulcorner \urcorner \llcorner \lrcorner  

Arrows

\Rrightarrow, \Lleftarrow  
\Rightarrow, \nRightarrow, \Longrightarrow \implies  
\Leftarrow, \nLeftarrow, \Longleftarrow  
\Leftrightarrow, \nLeftrightarrow, \Longleftrightarrow \iff  
\Uparrow, \Downarrow, \Updownarrow  
\rightarrow \to, \nrightarrow, \longrightarrow  
\leftarrow \gets, \nleftarrow, \longleftarrow  
\leftrightarrow, \nleftrightarrow, \longleftrightarrow  
\uparrow, \downarrow, \updownarrow  
\nearrow, \swarrow, \nwarrow, \searrow  
\mapsto, \longmapsto  
\rightharpoonup \rightharpoondown \leftharpoonup \leftharpoondown \upharpoonleft \upharpoonright \downharpoonleft \downharpoonright \rightleftharpoons \leftrightharpoons  
\curvearrowleft \circlearrowleft \Lsh \upuparrows \rightrightarrows \rightleftarrows \rightarrowtail \looparrowright  
\curvearrowright \circlearrowright \Rsh \downdownarrows \leftleftarrows \leftrightarrows \leftarrowtail \looparrowleft  
\hookrightarrow \hookleftarrow \multimap \leftrightsquigarrow \rightsquigarrow \twoheadrightarrow \twoheadleftarrow  

Special

\amalg \P \S \% \dagger \ddagger \ldots \cdots  
\smile \frown \wr \triangleleft \triangleright  
\diamondsuit, \heartsuit, \clubsuit, \spadesuit, \Game, \flat, \natural, \sharp  

Unsorted (new stuff)

\diagup \diagdown \centerdot \ltimes \rtimes \leftthreetimes \rightthreetimes  
\eqcirc \circeq \triangleq \bumpeq \Bumpeq \doteqdot \risingdotseq \fallingdotseq  
\intercal \barwedge \veebar \doublebarwedge \between \pitchfork  
\vartriangleleft \ntriangleleft \vartriangleright \ntriangleright  
\trianglelefteq \ntrianglelefteq \trianglerighteq \ntrianglerighteq  

For a little more semantics on these symbols, see the brief TeX Cookbook.

Larger expressions

Subscripts, superscripts, integrals

Feature Syntax How it looks rendered
Superscript a^2  
Subscript a_2  
Grouping 10^{30} a^{2+2}  
a_{i,j} b_{f'}  
Combining sub & super without and with horizontal separation x_2^3  
{x_2}^3  
Super super 10^{10^{8}}  
Preceding and/or additional sub & super \sideset{_1^2}{_3^4}\prod_a^b  
{}_1^2\!\Omega_3^4  
Stacking \overset{\alpha}{\omega}  
\underset{\alpha}{\omega}  
\overset{\alpha}{\underset{\gamma}{\omega}}  
\stackrel{\alpha}{\omega}  
Derivatives x', y'', f', f''  
x^\prime, y^{\prime\prime}  
Derivative dots \dot{x}, \ddot{x}  
Underlines, overlines, vectors \hat a \ \bar b \ \vec c  
\overrightarrow{a b} \ \overleftarrow{c d} \ \widehat{d e f}  
\overline{g h i} \ \underline{j k l}  
Arc (workaround) \overset{\frown} {AB}  
Arrows A \xleftarrow{n+\mu-1} B \xrightarrow[T]{n\pm i-1} C  
Overbraces \overbrace{ 1+2+\cdots+100 }^{5050}  
Underbraces \underbrace{ a+b+\cdots+z }_{26}  
Sum \sum_{k=1}^N k^2  
Sum (force \textstyle) \textstyle \sum_{k=1}^N k^2  
Sum in a fraction (default \textstyle) \frac{\sum_{k=1}^N k^2}{a}  
Sum in a fraction (force \displaystyle) \frac{\displaystyle \sum_{k=1}^N k^2}{a}  
Sum in a fraction (alternative limits style) \frac{\sum\limits^{^N}_{k=1} k^2}{a}  
Product \prod_{i=1}^N x_i  
Product (force \textstyle) \textstyle \prod_{i=1}^N x_i  
Coproduct \coprod_{i=1}^N x_i  
Coproduct (force \textstyle) \textstyle \coprod_{i=1}^N x_i  
Limit \lim_{n \to \infty}x_n  
Limit (force \textstyle) \textstyle \lim_{n \to \infty}x_n  
Integral \int\limits_{1}^{3}\frac{e^3/x}{x^2}\, dx  
Integral (alternative limits style) \int_{1}^{3}\frac{e^3/x}{x^2}\, dx  
Integral (force \textstyle) \textstyle \int\limits_{-N}^{N} e^x\, dx  
Integral (force \textstyle, alternative limits style) \textstyle \int_{-N}^{N} e^x\, dx  
Double integral \iint\limits_D \, dx\,dy  
Triple integral \iiint\limits_E \, dx\,dy\,dz  
Quadruple integral \iiiint\limits_F \, dx\,dy\,dz\,dt  
Line or path integral \int_{(x,y)\in C} x^3\, dx + 4y^2\, dy  
Closed line or path integral \oint_{(x,y)\in C} x^3\, dx + 4y^2\, dy  
Intersections \bigcap_{i=_1}^n E_i  
Unions \bigcup_{i=_1}^n E_i  

Fractions, matrices, multilines

Feature

Syntax

How it looks rendered

Fractions

\frac{1}{2}=0.5  

Small ("text style") fractions

\tfrac{1}{2} = 0.5  

Large ("display style") fractions

\dfrac{k}{k-1} = 0.5  

Mixture of large and small fractions

\dfrac{ \tfrac{1}{2}[1-(\tfrac{1}{2})^n] }{ 1-\tfrac{1}{2} } = s_n  

Continued fractions (note the difference in formatting)

\cfrac{2}{ c + \cfrac{2}{ d + \cfrac{1}{2} } } = a
\qquad
\dfrac{2}{ c + \dfrac{2}{ d + \dfrac{1}{2} } } = a
 

Binomial coefficients

\binom{n}{k}  

Small ("text style") binomial coefficients

\tbinom{n}{k}  

Large ("display style") binomial coefficients

\dbinom{n}{k}  

Matrices

\begin{matrix}
x & y \\
z & v 
\end{matrix}
 
\begin{vmatrix}
x & y \\
z & v 
\end{vmatrix}
 
\begin{Vmatrix}
x & y \\
z & v
\end{Vmatrix}
 
\begin{bmatrix}
0      & \cdots & 0      \\
\vdots & \ddots & \vdots \\ 
0      & \cdots & 0
\end{bmatrix}
 
\begin{Bmatrix}
x & y \\
z & v
\end{Bmatrix}
 
\begin{pmatrix}
x & y \\
z & v 
\end{pmatrix}
 
\bigl( \begin{smallmatrix}
a&b\\ c&d
\end{smallmatrix} \bigr)
 

Arrays

\begin{array}{|c|c||c|} a & b & S \\
\hline
0&0&1\\
0&1&1\\
1&0&1\\
1&1&0
\end{array}
 

Cases

f(n) = 
\begin{cases} 
n/2,  & \mbox{if }n\mbox{ is even} \\
3n+1, & \mbox{if }n\mbox{ is odd} 
\end{cases}
 

System of equations

\begin{cases}
3x + 5y +  z &= 1 \\
7x - 2y + 4z &= 2 \\
-6x + 3y + 2z &= 3
\end{cases}
 

Breaking up a long expression so it wraps when necessary

<math>f(x) = \sum_{n=0}^\infty a_n x^n</math>
<math>= a_0 + a_1x + a_2x^2 + \cdots</math>
   

Multiline equations

\begin{align}
f(x) & = (a+b)^2 \\
& = a^2+2ab+b^2
\end{align}
 
\begin{alignat}{2}
f(x) & = (a-b)^2 \\
& = a^2-2ab+b^2
\end{alignat}
 

Multiline equations with aligment specified (left, center, right)

\begin{array}{lcl}
z        & = & a \\
f(x,y,z) & = & x + y + z  
\end{array}
 
\begin{array}{lcr}
z        & = & a \\
f(x,y,z) & = & x + y + z     
\end{array}
 

Parenthesizing big expressions, brackets, bars

Feature !! Syntax !! How it looks rendered

Bad

( \frac{1}{2} )  

Good

\left ( \frac{1}{2} \right )  


You can use various delimiters with \left and \right:


Feature

Syntax

How it looks rendered

Parentheses

\left ( \frac{a}{b} \right )  

Brackets

\left [ \frac{a}{b} \right ] \quad \left \lbrack \frac{a}{b} \right \rbrack  

Braces (note the backslash before the braces in the code)

\left \{ \frac{a}{b} \right \} \quad \left \lbrace \frac{a}{b} \right \rbrace  
Angle brackets \left \langle \frac{a}{b} \right \rangle  
Bars and double bars (note: "bars" provide the absolute value function) \left | \frac{a}{b} \right \vert \left \Vert \frac{c}{d} \right \|  
Floor and ceiling functions: \left \lfloor \frac{a}{b} \right \rfloor \left \lceil \frac{c}{d} \right \rceil  
Slashes and backslashes \left / \frac{a}{b} \right \backslash  
Up, down and up-down arrows \left \uparrow \frac{a}{b} \right \downarrow \quad \left \Uparrow \frac{a}{b} \right \Downarrow \quad \left \updownarrow \frac{a}{b} \right \Updownarrow  
Delimiters can be mixed, as long as \left and \right are both used \left [ 0,1 \right )
\left \langle \psi \right |
 
 
Use \left. or \right. if you don't want a delimiter to appear: \left . \frac{A}{B} \right \} \to X  
Size of the delimiters \big( \Big( \bigg( \Bigg( \dots \Bigg] \bigg] \Big] \big]  
\big\{ \Big\{ \bigg\{ \Bigg\{ \dots \Bigg\rangle \bigg\rangle \Big\rangle \big\rangle  
\big| \Big| \bigg| \Bigg| \dots \Bigg\| \bigg\| \Big\| \big\|  
\big\lfloor \Big\lfloor \bigg\lfloor \Bigg\lfloor \dots \Bigg\rceil \bigg\rceil \Big\rceil \big\rceil  
\big\uparrow \Big\uparrow \bigg\uparrow \Bigg\uparrow \dots \Bigg\Downarrow \bigg\Downarrow \Big\Downarrow \big\Downarrow  
\big\updownarrow \Big\updownarrow \bigg\updownarrow \Bigg\updownarrow \dots \Bigg\Updownarrow \bigg\Updownarrow \Big\Updownarrow \big\Updownarrow  
\big / \Big / \bigg / \Bigg / \dots \Bigg\backslash \bigg\backslash \Big\backslash \big\backslash  

Alphabets and typefaces

Texvc cannot render arbitrary Unicode characters. Those it can handle can be entered by the expressions below. For others, such as Cyrillic, they can be entered as Unicode or HTML entities in running text, but cannot be used in displayed formulas.

Greek alphabet
\Alpha \Beta \Gamma \Delta \Epsilon \Zeta  
\Eta \Theta \Iota \Kappa \Lambda \Mu  
\Nu \Xi \Omicron \Pi \Rho \Sigma \Tau  
\Upsilon \Phi \Chi \Psi \Omega  
\alpha \beta \gamma \delta \epsilon \zeta  
\eta \theta \iota \kappa \lambda \mu  
\nu \xi \omicron \pi \rho \sigma \tau  
\upsilon \phi \chi \psi \omega  
\varepsilon \digamma \vartheta \varkappa  
\varpi \varrho \varsigma \varphi  
Blackboard Bold/Scripts
\mathbb{A} \mathbb{B} \mathbb{C} \mathbb{D} \mathbb{E} \mathbb{F} \mathbb{G}  
\mathbb{H} \mathbb{I} \mathbb{J} \mathbb{K} \mathbb{L} \mathbb{M}  
\mathbb{N} \mathbb{O} \mathbb{P} \mathbb{Q} \mathbb{R} \mathbb{S} \mathbb{T}  
\mathbb{U} \mathbb{V} \mathbb{W} \mathbb{X} \mathbb{Y} \mathbb{Z}  
\C \N \Q \R \Z  
boldface (vectors)
\mathbf{A} \mathbf{B} \mathbf{C} \mathbf{D} \mathbf{E} \mathbf{F} \mathbf{G}  
\mathbf{H} \mathbf{I} \mathbf{J} \mathbf{K} \mathbf{L} \mathbf{M}  
\mathbf{N} \mathbf{O} \mathbf{P} \mathbf{Q} \mathbf{R} \mathbf{S} \mathbf{T}  
\mathbf{U} \mathbf{V} \mathbf{W} \mathbf{X} \mathbf{Y} \mathbf{Z}  
\mathbf{a} \mathbf{b} \mathbf{c} \mathbf{d} \mathbf{e} \mathbf{f} \mathbf{g}  
\mathbf{h} \mathbf{i} \mathbf{j} \mathbf{k} \mathbf{l} \mathbf{m}  
\mathbf{n} \mathbf{o} \mathbf{p} \mathbf{q} \mathbf{r} \mathbf{s} \mathbf{t}  
\mathbf{u} \mathbf{v} \mathbf{w} \mathbf{x} \mathbf{y} \mathbf{z}  
\mathbf{0} \mathbf{1} \mathbf{2} \mathbf{3} \mathbf{4}  
\mathbf{5} \mathbf{6} \mathbf{7} \mathbf{8} \mathbf{9}  
Boldface (greek)
\boldsymbol{\Alpha} \boldsymbol{\Beta} \boldsymbol{\Gamma} \boldsymbol{\Delta} \boldsymbol{\Epsilon} \boldsymbol{\Zeta}  
\boldsymbol{\Eta} \boldsymbol{\Theta} \boldsymbol{\Iota} \boldsymbol{\Kappa} \boldsymbol{\Lambda} \boldsymbol{\Mu}  
\boldsymbol{\Nu} \boldsymbol{\Xi} \boldsymbol{\Pi} \boldsymbol{\Rho} \boldsymbol{\Sigma} \boldsymbol{\Tau}  
\boldsymbol{\Upsilon} \boldsymbol{\Phi} \boldsymbol{\Chi} \boldsymbol{\Psi} \boldsymbol{\Omega}  
\boldsymbol{\alpha} \boldsymbol{\beta} \boldsymbol{\gamma} \boldsymbol{\delta} \boldsymbol{\epsilon} \boldsymbol{\zeta}  
\boldsymbol{\eta} \boldsymbol{\theta} \boldsymbol{\iota} \boldsymbol{\kappa} \boldsymbol{\lambda} \boldsymbol{\mu}  
\boldsymbol{\nu} \boldsymbol{\xi} \boldsymbol{\pi} \boldsymbol{\rho} \boldsymbol{\sigma} \boldsymbol{\tau}  
\boldsymbol{\upsilon} \boldsymbol{\phi} \boldsymbol{\chi} \boldsymbol{\psi} \boldsymbol{\omega}  
\boldsymbol{\varepsilon} \boldsymbol{\digamma} \boldsymbol{\vartheta} \boldsymbol{\varkappa}  
\boldsymbol{\varpi} \boldsymbol{\varrho} \boldsymbol{\varsigma} \boldsymbol{\varphi}  
Italics
\mathit{A} \mathit{B} \mathit{C} \mathit{D} \mathit{E} \mathit{F} \mathit{G}  
\mathit{H} \mathit{I} \mathit{J} \mathit{K} \mathit{L} \mathit{M}  
\mathit{N} \mathit{O} \mathit{P} \mathit{Q} \mathit{R} \mathit{S} \mathit{T}  
\mathit{U} \mathit{V} \mathit{W} \mathit{X} \mathit{Y} \mathit{Z}  
\mathit{a} \mathit{b} \mathit{c} \mathit{d} \mathit{e} \mathit{f} \mathit{g}  
\mathit{h} \mathit{i} \mathit{j} \mathit{k} \mathit{l} \mathit{m}  
\mathit{n} \mathit{o} \mathit{p} \mathit{q} \mathit{r} \mathit{s} \mathit{t}  
\mathit{u} \mathit{v} \mathit{w} \mathit{x} \mathit{y} \mathit{z}  
\mathit{0} \mathit{1} \mathit{2} \mathit{3} \mathit{4}  
\mathit{5} \mathit{6} \mathit{7} \mathit{8} \mathit{9}  
Roman typeface
\mathrm{A} \mathrm{B} \mathrm{C} \mathrm{D} \mathrm{E} \mathrm{F} \mathrm{G}  
\mathrm{H} \mathrm{I} \mathrm{J} \mathrm{K} \mathrm{L} \mathrm{M}  
\mathrm{N} \mathrm{O} \mathrm{P} \mathrm{Q} \mathrm{R} \mathrm{S} \mathrm{T}  
\mathrm{U} \mathrm{V} \mathrm{W} \mathrm{X} \mathrm{Y} \mathrm{Z}  
\mathrm{a} \mathrm{b} \mathrm{c} \mathrm{d} \mathrm{e} \mathrm{f} \mathrm{g}  
\mathrm{h} \mathrm{i} \mathrm{j} \mathrm{k} \mathrm{l} \mathrm{m}  
\mathrm{n} \mathrm{o} \mathrm{p} \mathrm{q} \mathrm{r} \mathrm{s} \mathrm{t}  
\mathrm{u} \mathrm{v} \mathrm{w} \mathrm{x} \mathrm{y} \mathrm{z}  
\mathrm{0} \mathrm{1} \mathrm{2} \mathrm{3} \mathrm{4}  
\mathrm{5} \mathrm{6} \mathrm{7} \mathrm{8} \mathrm{9}  
Fraktur typeface
\mathfrak{A} \mathfrak{B} \mathfrak{C} \mathfrak{D} \mathfrak{E} \mathfrak{F} \mathfrak{G}  
\mathfrak{H} \mathfrak{I} \mathfrak{J} \mathfrak{K} \mathfrak{L} \mathfrak{M}  
\mathfrak{N} \mathfrak{O} \mathfrak{P} \mathfrak{Q} \mathfrak{R} \mathfrak{S} \mathfrak{T}  
\mathfrak{U} \mathfrak{V} \mathfrak{W} \mathfrak{X} \mathfrak{Y} \mathfrak{Z}  
\mathfrak{a} \mathfrak{b} \mathfrak{c} \mathfrak{d} \mathfrak{e} \mathfrak{f} \mathfrak{g}  
\mathfrak{h} \mathfrak{i} \mathfrak{j} \mathfrak{k} \mathfrak{l} \mathfrak{m}  
\mathfrak{n} \mathfrak{o} \mathfrak{p} \mathfrak{q} \mathfrak{r} \mathfrak{s} \mathfrak{t}  
\mathfrak{u} \mathfrak{v} \mathfrak{w} \mathfrak{x} \mathfrak{y} \mathfrak{z}  
\mathfrak{0} \mathfrak{1} \mathfrak{2} \mathfrak{3} \mathfrak{4}  
\mathfrak{5} \mathfrak{6} \mathfrak{7} \mathfrak{8} \mathfrak{9}  
Calligraphy/Script
\mathcal{A} \mathcal{B} \mathcal{C} \mathcal{D} \mathcal{E} \mathcal{F} \mathcal{G}  
\mathcal{H} \mathcal{I} \mathcal{J} \mathcal{K} \mathcal{L} \mathcal{M}  
\mathcal{N} \mathcal{O} \mathcal{P} \mathcal{Q} \mathcal{R} \mathcal{S} \mathcal{T}  
\mathcal{U} \mathcal{V} \mathcal{W} \mathcal{X} \mathcal{Y} \mathcal{Z}  
Hebrew
\aleph \beth \gimel \daleth  


Feature Syntax How it looks rendered
non-italicised characters \mbox{abc}    
mixed italics (bad) \mbox{if} n \mbox{is even}    
mixed italics (good) \mbox{if }n\mbox{ is even}    
mixed italics (more legible: ~ is a non-breaking space, while "\ " forces a space) \mbox{if}~n\ \mbox{is even}    

Color

Equations can use color:


  • {\color{Blue}x^2}+{\color{YellowOrange}2x}-{\color{OliveGreen}1}
     


  • x_{1,2}=\frac{-b\pm\sqrt{\color{Red}b^2-4ac}}{2a}
     


It is also possible to change the background color (since r59550), as in the following example:

Background Wikicode Rendering (in PNG)
White e^{i \pi} + 1 = 0  
\definecolor{orange}{RGB}{255,165,0}\pagecolor{orange}e^{i \pi} + 1 = 0  
Orange e^{i \pi} + 1 = 0  
\definecolor{orange}{RGB}{255,165,0}\pagecolor{orange}e^{i \pi} + 1 = 0  

See here for all named colors supported by LaTeX.

Note that color should not be used as the only way to identify something, because it will become meaningless on black-and-white media or for color-blind people. See Wikipedia:Manual of Style.

Formatting issues

Spacing

Note that TeX handles most spacing automatically, but you may sometimes want manual control.

Feature Syntax How it looks rendered
double quad space a \qquad b  
quad space a \quad b  
text space a\ b  
text space without PNG conversion a \mbox{ } b  
large space a\;b  
medium space a\>b [not supported]
small space a\,b  
no space ab  
small negative space a\!b  

Automatic spacing may be broken in very long expressions (because they produce an overfull hbox in TeX):

<math>0+1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+\cdots</math>
 

This can be remedied by putting a pair of braces { } around the whole expression:

<math>{0+1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+\cdots}</math>
 

Alignment with normal text flow

Due to the default css

img.tex { vertical-align: middle; }

an inline expression like   should look good.

If you need to align it otherwise, use <math style="vertical-align:-100%;">...</math> and play with the vertical-align argument until you get it right; however, how it looks may depend on the browser and the browser settings.

Also note that if you rely on this workaround, if/when the rendering on the server gets fixed in future releases, as a result of this extra manual offset your formulae will suddenly be aligned incorrectly. So use it sparingly, if at all.

Commutative diagrams

1 step method

 

<math>
\begin{array}{lcl}
 & X & \overset{f}\rightarrow & Z & \\
 & g \downarrow && \downarrow g'\\
 & Y & \underset{f'}\rightarrow & W & \\
\end{array}
</math>

3 step method

 
A sample commutative diagram, created in the manner described

To make a commutative diagram, there are three steps:

  1. write the diagram in TeX
  2. convert to SVG
  3. upload the file to Wikimedia Commons

Diagrams in TeX

Xy-pic[a] (online manual) is the most powerful and general-purpose diagram package in TeX. Diagrams created using it can be found at Commons: Category:Xy-pic diagrams.

Simpler packages include:

The following is a template for Xy-pic:

\documentclass[border=10pt]{standalone} % Crop to size, remove page numbers, leave margin
\usepackage[all]{xy} % Loading the XY-Pic package
\begin{document}
\SelectTips{eu}{} % Euler (shorter) arrowheads (tips)
$$
\xymatrix{
%%% Diagram goes here %%%
}
$$
\end{document}

Using postscript drivers may in some cases give smoother curves and will handle fonts differently:

\usepackage[all, ps, dvips]{xy}

Convert to SVG

Once you have produced your diagram in LaTeX (or TeX), you can convert it to an SVG file using the following sequence of commands:

pdflatex file.tex
pdf2svg file.pdf file.svg

The pdfcrop and pdf2svg utilities are needed for this procedure. You can alternatively use pdf2svg from PDFTron for the last step.

If you do not have pdfTeX (which is unlikely) you can use the following commands to replace the first step (TeX → PDF):

latex file.tex
dvipdfm file.dvi

In general, you will not be able to get anywhere with diagrams without TeX and Ghostscript, and the inkscape program is a useful tool for creating or modifying your diagrams by hand. There is also a utility pstoedit which supports direct conversion from Postscript files to many vector graphics formats, but it requires a non-free plugin to convert to SVG, and regardless of the format, this editor has not been successful in using it to convert diagrams with diagonal arrows from TeX-created files.

These programs are:

Upload the file

As the diagram is your own work, upload it to Wikimedia Commons, so that all projects (notably, all languages) can use it without having to copy it to their language's Wiki. (If you've previously uploaded a file to somewhere other than Commons, to Commons.)

Check size
Before uploading, check that the default size of the image is neither too large nor too small by opening in an SVG application and viewing at default size (100% scaling), otherwise adjust the -y option to dvips.
Name
Make sure the file has a meaningful name.
Upload
Login to Wikimedia Commons, then upload the file; for the Summary, give a brief description.

Now go to the image page and add a description, including the source code, using this template:

{{Information
 |description =
     {{en|1= '''Description [[:en:Link to WP page|topic]]'''}}
 |source = {{own}}, created as per:
  [[:en:Help:Displaying a formula#Commutative diagrams]];
  source code below.
 |date = '''The Creation Date, like 1999-12-31'''
 |author = '''[[User:YourUserName|Your Real Name]]'''
 |permission = {{self|PD-self '''(or [[commons:Licensing#Well-known licenses|other license]])'''
     |author = '''[[User:YourUserName|Your Real Name]]'''}}
}}

====TeX source====

<syntaxhighlight lang="latex">
 % TeX source here
</syntaxhighlight>
 
[[Category:Commutative diagrams]]
[[Category:Xy-pic diagrams]]
[[Category:Images with LaTeX source code]]
Source code
  • Include the source code in the image page, in the Source section of the {{Information}} template, so that the diagram can be edited in future.
  • Include the complete .tex file, not just the fragment, so future editors do not need to reconstruct a compilable file.
  • You may optionally make the source code section collapsible, using the {{cot}} or {{cob}} templates.
  • (Don't include it in the Summary section, which is just supposed to be a summary.)
License
The most common license for commutative diagrams is PD-self; some use PD-ineligible, especially for simple diagrams, or other licenses. Please do not use the GFDL, as it requires the entire text of the GFDL to be attached to any document that uses the diagram.
Description
If possible, link to a Wikipedia page relevant to the diagram. (The 1= is necessary if you use nest templates within the description, and harmless otherwise.)
Category
Include [[Category:Commutative diagrams]], so that it appears in commons:Category:Commutative diagrams. There are also subcategories, which you may choose to use.
Include image
Now include the image on the original page via [[File:Diagram.svg]]

Examples

A sample conforming diagram is commons:File:PSU-PU.svg.

Chemistry

Technically, <math chem>...</math> is a math tag with the extension mhchem enabled, according to the MathJax documentation.

Note, that the commands \cee and \cf are disabled, because they are marked as deprecated in the mhchem LaTeX package documentation.

Please note that there are still major issues with mhchem support in MediaWiki.

Molecular and Condensed formula

Markup Renders as
<math chem>H2O</math>

 

<math chem>Sb2O3</math>

 

<math chem>(NH4)2S</math>

 

Bonds

Markup Renders as
<math chem>C6H5-CHO</math>

 

<math chem>A-B=C{\equiv}D</math>

 

Charges

Markup Renders as
<math chem>H+</math>

 

<math chem>NO3-</math>

 

<math chem>CrO4^2-</math>

 

<math chem>AgCl2-</math>

 

<math chem>[AgCl2]-</math>

 

<math chem>Y^{99}+</math>
<math chem>Y^{99+}</math>

 
 

Addition Compounds and Stoichiometric Numbers

Markup Renders as
<math chem>MgSO4.7H2O</math>

 

<math chem>KCr(SO4)2*12H2O</math>

 

<math chem>{CaSO4.1/2H2O} + 1\!1/2H2O -> CaSO4.2H2O</math>

 

<math chem>{25/2O2} + C8H18 -> {8CO2} + 9H2O</math>

 

Greek characters

Markup Renders as
<math chem>\mu-Cl</math>

 

<math chem>[Fe(\eta^5-C5H5)2]</math>

 

Isotopes

Markup Renders as
<math chem>^{227}_{90}Th+</math>

 

<math chem>^0_{-1}n-</math>

 

States

Markup Renders as
<math chem>H2_{(aq)}</math>

 

<math chem>CO3^{2-}{(aq)}</math>

 

(Italic) Math

Oxidation States

Precipitate

Reaction Arrows

Markup Renders as
<math chem>A ->[x] B</math>

 

<math chem>A ->[\text{text above}][\text{text below}] B</math>

 

Comparison of arrow symbols
Markup Renders as
<math>\rightarrow</math>

 

<math>\rightleftarrows</math>

 

<math>\rightleftharpoons</math>

 

<math>\leftrightarrow</math>

 

<math>\longrightarrow</math>
<math chem>-></math>

 
 

<math chem><=></math>

 

<math>\longleftrightarrow</math>
<math chem><-></math>

 
 

Examples

Chemistry

<math chem>C6H5-CHO</math>
 
<math chem>{SO4^{2-}} + Ba^2+ -> BaSO4 v</math>
 
<math chem>H2O</math>
 
<math chem>Sb2O3</math>
 
<math chem>H+</math>
 
<math chem>CrO4^2-</math>
 
<math chem>AgCl2-</math>
 
<math chem>[AgCl2]-</math>
 
<math chem>Y^{99}+</math>
 
<math chem>Y^{99+}</math>
 
<math chem>H2_{(aq)}</math>
 
<math chem>NO3-</math>
 
<math chem>(NH4)2S</math>
 

Examples of implemented TeX formulas

Quadratic polynomial

Markup
<math>ax^2 + bx + c = 0</math>
Renders as  

Quadratic formula

Markup
<math>x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}</math>
Renders as  

Tall parentheses and fractions

Markup
<math>2 = \left( \frac{\left(3-x\right) \times 2}{3-x} \right)</math>
Renders as  
Markup
<math>S_{\text{new}} = S_{\text{old}} - \frac{ \left( 5-T \right) ^2} {2}</math>
Renders as  

Integrals

Markup
<math>\int_a^x \int_a^s f(y)\,dy\,ds = \int_a^x f(y)(x-y)\,dy</math>
Renders as  
Markup
<math>\int_e^{\infty}\frac {1}{t(\ln t)^2}dt = \left. \frac{-1}{\ln t} \right\vert_e^\infty = 1</math>
Renders as  

Matrices and determinants

Markup
<math>\det(\mathsf{A}-\lambda\mathsf{I}) = 0</math>
Renders as  

Summation

Markup
<math>\sum_{i=0}^{n-1} i</math>
Renders as  
Markup
<math>\sum_{m=1}^\infty\sum_{n=1}^\infty\frac{m^2 n}{3^m\left(m 3^n + n 3^m\right)}</math>
Renders as  

Differential equation

Markup
<math>u'' + p(x)u' + q(x)u=f(x),\quad x>a</math>
Renders as  

Complex numbers

Markup
<math>|\bar{z}| = |z|,
|(\bar{z})^n| = |z|^n,
\arg(z^n) = n \arg(z)</math>
Renders as  

Limits

Markup
<math>\lim_{z\to z_0} f(z)=f(z_0)</math>
Renders as  

Integral equation

Markup
<math>\phi_n(\kappa) =
\frac{1}{4\pi^2\kappa^2} \int_0^\infty
\frac{\sin(\kappa R)}{\kappa R}
\frac{\partial}{\partial R}
\left [ R^2\frac{\partial D_n(R)}{\partial R} \right ] \,dR</math>
Renders as  

Example

Markup
<math>\phi_n(\kappa) =
0.033C_n^2\kappa^{-11/3},\quad
\frac{1}{L_0}\ll\kappa\ll\frac{1}{l_0}</math>
Renders as  

Continuation and cases

Markup
<math>f(x) =
  \begin{cases}
    1 & -1 \le x < 0 \\
    \frac{1}{2} & x = 0 \\
    1 - x^2 & \text{otherwise}
  \end{cases}</math>
Renders as  

Prefixed subscript

Markup
 <math>{}_pF_q(a_1,\dots,a_p;c_1,\dots,c_q;z)
= \sum_{n=0}^\infty
\frac{(a_1)_n\cdots(a_p)_n}{(c_1)_n\cdots(c_q)_n}
\frac{z^n}{n!}</math>
Renders as  

Fraction and small fraction

Markup
<math>\frac{a}{b}\ \tfrac{a}{b}</math>
Renders as  

Area of a quadrilateral

Markup
<math>S=dD\sin\alpha</math>
Renders as  

Volume of a sphere-stand

Markup
<math> V = \frac{1}{6} \pi h \left [ 3 \left ( r_1^2 + r_2^2 \right ) + h^2 \right ] </math>
Renders as  

Multiple equations

The altered newline code \\[0.6ex] below adds a vertical space between the two lines of length equal to   times the height of a single 'x' character.

Markup
<math>\begin{align}
u & = \tfrac{1}{\sqrt{2}}(x+y) \qquad & x &= \tfrac{1}{\sqrt{2}}(u+v) \\[0.6ex]
v & = \tfrac{1}{\sqrt{2}}(x-y) \qquad & y &= \tfrac{1}{\sqrt{2}}(u-v)
\end{align}</math>
Renders as  


Cite error: <ref> tags exist for a group named "lower-alpha", but no corresponding <references group="lower-alpha"/> tag was found