This is a guide for those who want to learn use $\LaTeX$ or simple formatting. If you want to contribute on brilliant, then you should use $\LaTeX$ in many cases. This makes your posts more readable.
When you don't know how to write a symbol, then use the Google. I will post there only the important symbols.
There are lots of $\LaTeX$ guides, but I think my guide will be the most readale and complete. Let's start the learning.
$\LaTeX$ is a formatting(or markdown) language to format documents or write formulas. In this web page we can't format documents, therefore lots of commands isn't working.
This paragraph will help you to format your posts without $\LaTeX$.
What you type  What you get 
*italics* or _italics_  italics 
**bold** or __bold__  bold 
You can combine the two styles like these:
***Hello!***
*__Hello!__*
___Hello!___
All possible combinations is correct. Each will appear as Hello!.
See this example:
I
love
to
do
it
I love to do this
Now try it with two or more spaces at the end of the lines:
I
love
to
do
it
I
love
to
do
this
Now try to take empty spaces:
I
love
to
do
it
I
love
to
do
this
If you fil the empty lines with spaces you will get the same result. If you want to take more empty sapces you should use $\LaTeX$ codes. But this isn't the $\LaTeX$ section, so let's continue.
> It will appear like this quote
It will appear like this quote
Let's see some examples:
> This
is
an
example
This is an example
Now try it with two or more spaces at the end of each lines:
> This
is
an
example
This
is
an
example
Now try to connect two quotes:
> This is
> an example
This is
an example
If you want to separate them, then you should write something between them(this can be an empty $\LaTeX$ code too):
> This is
an
> example
This is
an
example
 buletted
or * bulleted
or + bulleted
and 1. numbered
Usefull things:
connected to the list)  You should take a space after the  sign
I will show the examples with only bulleted lists:
This isn't a
 bulleted list
 bulleted list
 bulleted list
continue
 shifted list
This isn't a  bulleted list
bulleted list
bulleted list
continue
$\\$
Let's see this one:
* It
won't
* break
It
won't
break $\\$
If you should write a date:
1956. Doesn't work
1956\. Yeah
$\\$
[<link text>](<link>)
Link text will appear.
[I'm happy](https://translate.google.com/?hl=hu#view=home&%3Bop=translate&%3Bsl=en&%3Btl=hu&%3Btext=I'm%20happy.&op=translate&sl=en&tl=hu&text=I'm%20happy)
There is the empty link
[I'm empty](#)
If you should use a link many times you can define links:
[link][id1]
[id1]: https://brilliant.org/discussions/thread/mathprovemarathon/ "Title"
link.
You can use links in $\LaTeX$ too, but this is unnecessary.
When you upload a picture, then you will get a code. You should only insert it, if you placed to the wrong place(or if you want to insert it to the comment section). But when you want to use a
picture from the internet, then you should only copy the link of the picture: ![text under the picture](<link or uploaded link>){: .<position>}
The position can be:
left
,center
,right
. If you delete the {} brackets, then it will be left aligned.
Let's see an example for the three positions and how to combine links and pictures:
![](https://www.shutterstock.com/blog/wpcontent/uploads/sites/5/2019/07/ManSilhouette.jpg){: .left}
[![](https://www.shutterstock.com/blog/wpcontent/uploads/sites/5/2019/07/ManSilhouette.jpg){: .center}](https://d.newsweek.com/en/full/520858/supermoonmoonsmartphonephotopicture.jpg)
Click to the picture!
![](https://www.shutterstock.com/blog/wpcontent/uploads/sites/5/2019/07/ManSilhouette.jpg){: .right}
As you can see if the picture isn't center aligned, then the text after the picture's link will appear next to the picture.
The code of the gif files are the same.
You can give a title to your picture. It won't appear: ![<text under the picture>](<link> "<Title>"){: .<position>}
. You can define links to pictures too.
When we are talking about commands, then we use these:
`readln()`
readln()
We can take lots of `
before it, but then we should take the same amount of this signs after it.
If we want line breaks without break the code block:
```python
print "This is the best sentence"
```
1 

Sometimes the text after the code block doesn't appear. You should only place a title after the code and it will be good.
If you don't give the name of the programming language:
1 

You should take an empty line before it. If the text after the code block doesn't appear, then take a #
after the block.
$\\$
If you take 4 spaces, then
it will appear like you typed
similar to the quote
this will be if you take more than 4 spaces
$\\$
123
4wide column
same
othertable:)
longerrowthanthe first
1  2  3 
4  wide column  
same 
other  table  :)  
longer  row  than  the first 
We can create 6 different titles(we can close them, but this is unnecessary):
# I'm your ego
## This is sometimes underlined ##
### I'm your IQ
#### Interesting
##### Nothing #####
###### Thinking
_ =Shift and ``
If under a text we take a 
or =
these will make a title. If we take an empty line, then these won't:
_
title 1
=
title 2


* * *
*
 
@<name>
When you start the typing to mention somebody, then the web page will give you options. If you don't choose one, then it won't work. You should choose the correct option. If the web page don't give you the required name, then continue the typing or try to type the name another way(for example without space).
The interpreter should distinct the $\LaTeX$ codes, so we should mark them. We can mark two types of $\LaTeX$ placement:
The first type of $\LaTeX$ placement will appear like this $1+2=3$, but the second will like this $1+2=3$. Both codes are placed into the sentence, but the second makes a break line before and after itself and the second is center aligned.
Spaces sometimes are allowed, sometimes they are necessary but sometimes they are unallowed. Let's see the rules:
Rule  Example code  How will ppear 
Between the brackets the spaces are unallowed  \ ( 1+3\ )  \ ( 1+3\ ) 
In a command the spaces don't allowed  \$$(\ta n(x)\)  $\ta n(x)$ 
After a command if the next character is a letter, then the space is necessary  \$$(\tanx\)  $\tanx$ 
In other cases the spaces are allowed  \$$(3$\;\;$+$\;\;$4 = 7\)  $3 + 4 = 7$ 
Line breaks are allowed when spaces are allowed  \$$(1 + $\\$ 3 = 4\)  $1 + 3 = 4$ 
But these spaces won't appear. There you can see how to take a space:
Code  Appearance  Note 
\,  $te\,xt$  
\:  $te\:xt$  
\;  $te\;xt$  
\!  $te\!xt$  If you take more\! : $te\!\!\!\!xt$ 
~  $te~xt$ 
Or you can insert a text or outside the brackets you can take one space. With these $\LaTeX$ codes you can take longer spaces.
You can make special spaces:
{\kern 1pt} {\kern 10pt} {\kern 100pt}\\
\hspace{1pt} \hspace{10pt} \hspace{100pt}
${\kern 1pt} {\kern 10pt} {\kern 100pt}\\ \hspace{1pt} \hspace{10pt} \hspace{100pt}$
$pt$ is a given length like $cm$ and $mm$. In$\LaTeX$ (and in web building) there are other units, but the main units are: $\text{pt, px, em}$
Let's see how to make line breakes with special length:
4\\[30px]5
\(4\\[30px]5\)
You can give not integer numbers and negative numbers also.
54
5\hspace{0.7px}4
5\hspace{4px}4
$54$
$5\hspace{0.7px}4$
$5\hspace{4px}4$
$0.7=.7$
Here is some information about other length:
$\rule{5in}{10px}$ 5 in
$\rule{5cm}{10px}$ 5 cm
$\rule{5cc}{10px}$ 5 cc
$\rule{5nc}{10px}$ 5 nc
$\rule{5pc}{10px}$ 5 pc
$\rule{5em}{10px}$ 5 em
$\rule{5ex}{10px}$ 5 ex
$\rule{5mm}{10px}$ 5 mm
$\rule{5dd}{10px}$ 5 dd
$\rule{5nd}{10px}$ 5 nd
$\rule{5px}{10px}$ 5 px
$\rule{5bp}{10px}$ 5 bp
$\rule{5pt}{10px}$ 5 pt
$\rule{5sp}{10px}$ 5 sp
What you type  What you get  Note 
2=2  $2=2$  
1+2  $1+2$  
4*6  $4*6$  If you use other commands, then it will appear better 
4\times6  $4\times6$  If you are on mobile, then maybe you can find it at the symbols 
4\cdot6  $4\cdot6$  
8/4  $8/4$  you can use other commands too 
8\div4  $8\div4$  On mobile you can write it without code 
\frac{8}{4}  $\frac{8}{4}$  You can use modificators. \frac 123 will be $\frac 123$ 
{3\choose2}  ${3\choose2}$  
\binom{3}{2}  $\binom{3}{2}$  
2^3  $2^3$  If you want to write $2^{33}$, than you should write 2^{33} , without the { and } brackets it will appear like this $2^33$ 
2^{3^3}  $2^{3^3}$  If you don't write brackets: 2^3^3 
A_1  $A_1$  Same way as ^ if you want to write more characters you should use { and } brackets 
A_{1_2}  $A_{1_2}$  
\sqrt{3}  $\sqrt{3}$  
\sqrt[4]{5}  $\sqrt[4]{5}$  
\parallel  $\parallel$  
\perp  $\perp$ 
After the basic operators let's see some often used commands. There are some built in functions like \tan
, \log
, \gcd
, \mod
.... We can avoid them, but using them is easier. Let's see an
example: \tan(x)=1
and tan(x)
will appear like $\tan(x)$ and $tan(x)$.
\left ( \right )  $\left ( \right )$ 
\left \ \right \  $\left \ \right \$ 
\left [ \right ]  $\left [ \right ]$ 
\left \langle \right \rangle  $\left \langle \right \rangle$ 
\left \{ \right \}  $\left \{ \right \}$ 
\left \lfloor \right \rfloor  $\left \lfloor \right \rfloor$ 
\left  \right   $\left  \right $ 
\left \lceil \right \rceil  $\left \lceil \right \rceil$ 
Sometimes we should use modificators. Let's see an example: $\frac{\frac{2}{\frac{5}{6}+7}+3}{4^8}$. As you can see this is too small. The modificators help us to set the size of the operators.
If we use the \displaystyle
modificator before each fraction, then it will set the size automatically:
\displaystyle\frac{\displaystyle\frac{2}{\displaystyle\frac{5}{6}+7}+3}{4^8}  $\displaystyle\frac{\displaystyle\frac{2}{\displaystyle\frac{5}{6}+7}+3}{4^8}$ 
This is a long way to solve this problem, so we can use \dfrac{}{}
. We will get the same result. With fractions there are some more modificators. Let's all of them in one table:
Code  Appearance 
\frac{2+\frac{1}{5}}{\frac{7}{6}+4}  $\frac{2+\frac{1}{5}}{\frac{7}{6}+4}$ 
\displaystyle\frac{2+\displaystyle\frac{1}{5}}{\displaystyle\frac{7}{6}+4}  $\displaystyle\frac{2+\displaystyle\frac{1}{5}}{\displaystyle\frac{7}{6}+4}$ 
\dfrac{2+\dfrac{1}{5}}{\dfrac{7}{6}+4}  $\dfrac{2+\dfrac{1}{5}}{\dfrac{7}{6}+4}$ 
\cfrac{2+\cfrac{1}{5}}{\cfrac{7}{6}+4}  $\cfrac{2+\cfrac{1}{5}}{\cfrac{7}{6}+4}$ 
\tfrac{2+\tfrac{1}{5}}{\tfrac{7}{6}+4}  $\tfrac{2+\tfrac{1}{5}}{\tfrac{7}{6}+4}$ 
Here is two examples with $\!\!\!\!\mod\!$:
Code  Appearance 
2\mod4  $2\mod4$ 
2\bmod4  $2\bmod4$ 
2\pmod4  $2\pmod4$ 
The \displaystyle
won't do anything.
In some cases the \displaystyle
works only. Let's see some examples(I wrote the modificators before the operators):
Original  Modificated 
$2^{3^{4^{5^6}}}$  $2\displaystyle^{3\displaystyle^{4\displaystyle^{5\displaystyle^6}}}$ 
$A_{B_{C_{D_E}}}$  $A\displaystyle_{B\displaystyle_{C\displaystyle_{D\displaystyle_E}}}$ 
$\sum_a^b$  $\displaystyle\sum_a^b$ 
Sometimes modificators cause some problem:
$(\dfrac{\dfrac{4}{6}+2}{1})$
You can try the \displaystyle
won't help. When we use brackets we use the \left
and the \right
modificators:
\left ( \dfrac{\dfrac{4}{6}+2}{1} \right )  $\left ( \dfrac{\dfrac{4}{6}+2}{1} \right )$ 
But sometimes we use only one bracket(usually when we are working with a matrix). Let's see an example:
\left  \dfrac{\dfrac{4}{6}+2}{1}  \left  \dfrac{\dfrac{4}{6}+2}{1} 
As you can see it's not working perfectly. When we start a bracket with a modificator then we should mark the pair of it and same way we can't end a bracket if we didn't marked the pair of it. The solution is easy:
\left  \dfrac{\dfrac{4}{6}+2}{1} \right.  $\left  \dfrac{\dfrac{4}{6}+2}{1}\right.$ 
You can make left and center aligned equations already. But sometimes we make lots of modifications on only one side of the equation. Let's see that:
\begin{align}
A&=(4x+5)^28\\
&=16x^2+40x+258\\
&=16x^2+40x+17
\end{align}
$\begin{aligned} A&=(4x+5)^28\\ &=16x^2+40x+258\\ &=16x^2+40x+17 \end{aligned}$
& means that where will the lines aligned. So the next characters after the & signs will make a straight vertical line. The \ signs means the line break. We should not take a line break after these signs, when we write the code, but if we take we can modificate easier it. We can use align*
too, but it doesn't make anything. Let's see an interesting example:
\begin{align}
1&=333&=333&=22&=22&333&=22&=1\\
1&=22&22&=333&=22&1&=1&=22&=5&=1\\
4444&=1&=1&=1&=333&333&=4444&=1&=22&=55555\\
&&&&4444\\
22
\end{align}
$\begin{aligned} 1&=333&=333&=22&=22&333&=22&=1\\ 1&=22&22&=333&=22&1&=1&=22&=5&=1\\ 4444&=1&=1&=1&=333&333&=4444&=1&=22&=55555\\ &&&&4444\\ 22 \end{aligned}$
Only the often used special characters:
\rightarrow  $\rightarrow$  \Rightarrow  $\Rightarrow$ 
\leftarrow  $\leftarrow$  \Leftarrow  $\Leftarrow$ 
\uparrow  $\uparrow$  \Uparrow  $\Uparrow$ 
\downarrow  $\downarrow$  \Downarrow  $\Downarrow$ 
\pm  $\pm$  \mp  $\mp$ 
\leq  $\leq$  \geq  $\geq$ 
\lfloor  $\lfloor$  \rfloor  $\rfloor$ 
\lceil  $\lceil$  \rceil  $\rceil$ 
\therefore  $\therefore$  \because  $\because$ 
\angle  $\angle$  \triangle  $\triangle$ 
\equiv  $\equiv$  \approx  $\approx$ 
\in  $\in$  \ni  $\ni$ 
\ll  $\ll$  \gg  $\gg$ 
\neq  $\neq$  
x ,=AltGr+W  $x$  
\infty  $\infty$ 
As you can see there are modifications of the arrows. If you start with a big letter you will get a double arrow. You can use modificators too:
long
,leftright
,updown
There are lots of characters. I won't write all of them. Here you can see more characters.
Let's see the big operators:
\int  $\int$ 
\iint  $\iint$ 
\oint  $\oint$ 
\sum  $\sum$ 
\prod  $\prod$ 
\bigcap  $\bigcap$ 
\bigcup  $\bigcup$ 
\Alpha and \alpha  $\Alpha$ and $\alpha$  \Nu and \nu  $\Nu$ and $\nu$ 
\Beta and \beta  $\Beta$ and $\beta$  \Xi and \xi  $\Xi$ and $\xi$ 
\Gamma and \gamma  $\Gamma$ and $\gamma$  \Omicron and \omicron  $\Omicron$ and $\omicron$ 
\Delta and \delta  $\Delta$ and $\delta$  \Pi , \pi and \varpi  $\Pi$, $\pi$ and $\varpi$ 
\Epsilon , \epsilon and \varepsilon  $\Epsilon$, $\epsilon$ and $\varepsilon$  \Rho , \rho and \varrho  $\Rho$, $\rho$ and $\varrho$ 
\Zeta and \zeta  $\Zeta$ and $\zeta$  \Sigma , \sigma and \varsigma  $\Sigma$, $\sigma$ and $\varsigma$ 
\Eta and \eta  $\Eta$ and $\eta$  \Tau and \tau  $\Tau$ and $\tau$ 
\Theta , \theta and \vartheta  $\Theta$, $\theta$ and $\vartheta$  \Upsilon and \upsilon  $\Upsilon$ and $\upsilon$ 
\Iota and \iota  $\Iota$ and $\iota$  \Phi , \phi and \varphi  $\Phi$, $\phi$ and $\varphi$ 
\Kappa , \kappa and \varkappa  $\Kappa$, $\kappa$ and $\varkappa$  \Chi and \chi  $\Chi$ and $\chi$ 
\Lambda and \lambda  $\Lambda$ and $\lambda$  \Psi and \psi  $\Psi$ and $\psi$ 
\Mu and \mu  $\Mu$ and $\mu$  \Omega and \omega  $\Omega$ and $\omega$ 
{}'  ${a}'$ 
{}''  ${a}''$ 
\dot{}  $\dot{a}$ 
\ddot{}  $\ddot{a}$ 
\hat{}  $\hat{a}$ 
\check{}  $\check{a}$ 
\grave{}  $\grave{a}$ 
\acute{}  $\acute{a}$ 
\tilde{}  $\tilde{a}$ 
\breve{}  $\breve{a}$ 
\bar{}  $\bar{a}$ 
\vec{}  $\vec{a}$ 
\not{}  $\not{a}$ 
^{\circ}  $a^{\circ}$ 
\widetilde{}  $\widetilde{abc}$ 
\widehat{}  $\widehat{abc}$ 
\overleftarrow{}  $\overleftarrow{abc}$ 
\overrightarrow{}  $\overrightarrow{abc}$ 
\overline{}  $\overline{abc}$ 
\underline{}  $\underline{abc}$ 
\overbrace{}  $\overbrace{abc}$ 
\underbrace{}  $\underbrace{abc}$ 
\overset{}{}  $\overset{123}{abc}$ 
\underset{}{}  $\underset{123}{abc}$ 
\xrightarrow[]{}  $\xrightarrow[123]{abc}$ 
\xleftarrow[]{}  $\xleftarrow[123]{abc}$ 
In every case the first brackets contain the
123
. You can see we can't useoverset
andunderset
at the same time. Instead we can use arrays and matrices. The brackets can contain arrows also: $\overset{\Delta t}{\rightarrow}$
And there is one interesting thing:
\boxed{12.5}=\fbox{12.5}
$\boxed{12.5}=\fbox{12.5}$
And we can do this:
\cancel{123456789}
$\cancel{123456789}$
\text{}
between the brackets everything will appear.
\text{I'm happy...}  $\text{I'm happy...}$ 
Code  Appearance  Code  Appearance  
\textnormal{}  $\textnormal{BIG small}$  \mathnormal{}  $\mathnormal{BIG small}$  
\textup{}  $\textup{BIG small}$  \boldsymbol{}  $\boldsymbol{BIG small}$  Note: with this code we can print bold symbols: $\boldsymbol{\uparrow}$ 
\textbf{}  $\textbf{BIG small}$  \mathbf{}  $\mathbf{BIG small}$  
\textit{}  $\textit{BIG small}$  \mathit{}  $\mathit{BIG small}$  
\textrm{}  $\textrm{BIG small}$  \mathrm{}  $\mathrm{BIG small}$  
\textsf{}  $\textsf{BIG small}$  \mathsf{}  $\mathsf{BIG small}$  
\textrm{}  $\textrm{BIG small}$  \mathrm{}  $\mathrm{BIG small}$  
\texttt{}  $\texttt{BIG small}$  \mathbb{}  $\mathbb{BIG small}$  
\textmd{}  $\textmd{BIG small}$  
\mathcal{}  $\mathcal{BIG small}$  
\mathfrak{}  $\mathfrak{BIG small}$ 
These are unnecessary codes, you shouldn't learn them. As you can see only the text formats will display the spaces.
\tiny  $\tiny\text{tiny}$ 
\scriptsize  $\scriptsize\text{scriptsize}$ 
\footnotesize  $\footnotesize\text{footnotesize}$ 
\small  $\small\text{small}$ 
\normalsize  $\normalsize\text{normalsize}$ 
\large  $\large\text{large}$ 
\Large  $\Large\text{Large}$ 
\LARGE  $\LARGE\text{LARGE}$ 
\huge  $\huge\text{huge}$ 
\Huge  $\Huge\text{Huge}$ 
If we place the code in a title:
$\Huge \text{Bubu}$
There are built in colores:
\red{}
, \blue{}
, \green{}
, \orange{}
etc.
$\red{red rat}$
We can use \color{}
. Between the brackets we should give the name of the color. This will be active until you don't change the color again.
There are two ways to give the color:
\color{red}
, \color{blue}
, \color{black}
\color{#<code>}
Let's see an example to the second: If our color is the basic red, then with RGB($\color{#ff0000}\text{Red}\color{#00ff00}\text{Green}\color{#0000ff}\text{Blue}$)
coloring:
$\color{#ff0000}\text{Red}=100\%$  $100\%=(256)_{10}$  $(256)_{10}=(FF)_{16}$ 
$\color{#00ff00}\text{Green}=0\%$  $0\%=(0)_{10}$  $(0)_{10}=(00)_{16}$ 
$\color{#0000ff}\text{Blue}=0\%$  $0\%=(0)_{10}$  $(0)_{10}=(00)_{16}$ 
So the code will be \color{#FF0000}
: $\color{#ff0000}\text{red}$
Let's see a complex color: #4DA3EC
$\color{#4da3ec} color$
Here you can set the color and get the code of it.
If we use the color
command between two { }
brackets, then the text after the brackets won't be colored:
{\color{green}green}black
${\color{#20A900}green}black$
Let's see an interesting example:
\color{red}red{\color{green}green}unknown
$\color{#D61F06}red{\color{#20A900}green}unknown$
We can use \textcolor{}
also:
\textcolor{red}{red}
$\textcolor{#D61F06}{red}$
\textcolor{red}red
$\textcolor{#D61F06}red$
But we can make color boxes:
\colorbox{blue}{black\color{#FFFFFF}white}
$\colorbox{#3D99F6}{black\color{#ffffff}white}$
And we can make color boxes with border:
\fcolorbox{red}{blue}{\text{The text command include the whole text, but the brackets are necessary}}
$\fcolorbox{#D61F06}{#3D99F6}{\text{The text command include the whole text, but the brackets are necessary}}$
Matrices are similar to tables and to the aligned equations. & means the next column an \ means the next row(If \ is annoying, then you can use \cr
):
\begin{matrix}
1 & 2 & 3\\
4 & 5 & 6
\end{matrix}
$\begin{matrix} 1 & 2 & 3\\ 4 & 5 & 6 \end{matrix}$
Like with tables, there you can skip columns and you can make longer rows than the first:
\begin{matrix}
1 & 2 & 3\\
1 & 2 &
3 & 4 & 5\\
&&3&&5
\end{matrix}
$\begin{matrix} 1 & 2 & 3\\ 1 & 2 & 3 & 4 & 5\\ &&3&&5 \end{matrix}$
You can see if we won't write a whole line we can skip the & symbols. And you can see also that I taked a line break, but it doesn't displayed.
Let's see the types of the matrices:
pmatrix
\begin{pmatrix}
1 & 2 & 3\\
4 & 5 & 6
\end{pmatrix}
$\begin{pmatrix} 1 & 2 & 3\\ 4 & 5 & 6 \end{pmatrix}$
bmatrix
\begin{bmatrix}
1 & 2 & 3\\
4 & 5 & 6
\end{bmatrix}
$\begin{bmatrix} 1 & 2 & 3\\ 4 & 5 & 6 \end{bmatrix}$
Bmatrix
\begin{Bmatrix}
1 & 2 & 3\\
4 & 5 & 6
\end{Bmatrix}
$\begin{pmatrix} 1 & 2 & 3\\ 4 & 5 & 6 \end{pmatrix}$
vmatrix
\begin{vmatrix}
1 & 2 & 3\\
4 & 5 & 6
\end{vmatrix}
$\begin{vmatrix} 1 & 2 & 3\\ 4 & 5 & 6 \end{vmatrix}$
Vmatrix
\begin{Vmatrix}
1 & 2 & 3\\
4 & 5 & 6
\end{Vmatrix}
$\begin{Vmatrix} 1 & 2 & 3\\ 4 & 5 & 6 \end{Vmatrix}$
But we can use special matrices too:
\left\{\left. \begin{matrix}
1 & 3 & 5\\
7 & 4 & 9
\end{matrix}\right \right.
$\left\{\left. \begin{matrix} 1 & 3 & 5\\ 7 & 4 & 9 \end{matrix}\right \right.$
But we can place a matrix into another matrix:
\begin{matrix}
1 & \begin{matrix}
2 & 3\\
4 & 5
\end{matrix}\\
6 & 7
\end{matrix}
$\begin{matrix} 1 & \begin{matrix} 2 & 3\\ 4 & 5 \end{matrix}\\ 6 & 7 \end{matrix}$
We can insert horizontal lines into the matrix with \hline
:
\begin{matrix}
2 & 4\\
\hline 5 & 6
\end{matrix}
$\begin{matrix} 2 & 4\\ \hline 5 & 6 \end{matrix}$
If we need a vertical line, then we should use two matrices or use an array. Let's see the arrays.
The arrays are similar to matrices, but when we begin an array, then we should give the align of each colummn:
\begin{array}{<align>}
<array>
\end{array}
<align>
can be:
If we have more columns than that we have declared we will get an error message. But we can skip the empty columns. Let's see an example:
\begin{array}{lcr}
7777777 & 4444 & 666666\\
4444 & 1\\
22&&999999999
\end{array}
$\begin{array}{lcr} 7777777 & 4444 & 666666\\ 4444 & 1\\ 22&&999999999 \end{array}$
Now let's see how to insert a vertical line:
\begin{array}{cc}
1 & 2\\
3 & 4\\
5 & 6\\
\end{array}
$\begin{array}{cc} 1 & 2\\ 3 & 4\\ 5 & 6\\ \end{array}$
\begin{cases}
y=1 & x=5 \\
y=2 & x=4 \\
y=3 & x=3 \\
y=4 & x=2 \\
y=5 & x=1
\end{cases}
$\begin{cases} y=1 & x=5 \\ y=2 & x=4 \\ y=3 & x=3 \\ y=4 & x=2 \\ y=5 & x=1 \end{cases}$ You can't add new columns. But if you insert a matrix, then you can solve it.
There are lots of dots. Here you can see the main codes(from wikibooks):
\dots  $\dots$  Generic dots (ellipsis), to be used in text (outside formulae as well). It automatically manages whitespaces before and after itself according to the context, it's a higher level command. 
\ldots  $\ldots$  The output is similar to the previous one, but there is no automatic whitespace management; it works at a lower level. 
\cdots  $\cdots$  These dots are centered relative to the height of a letter. There is also the binary multiplication operator, \cdot, mentioned below. 
\vdots  $\vdots$  vertical dots 
\ddots  $\ddots$  diagonal dots 
This web page doesn't support all $\LaTeX$ codes. Therefore we can't use lots of not mathematical codes. I think only basic formatting, chemical equations and square drawing are supported. Let's see the chemical equations:
You can already write chemical equations:
\text{CH}_4+2\text{O}_2\rightarrow2\text{H}_2\text{O}+\text{CO}_2
$\text{CH}_4+2\text{O}_2\rightarrow2\text{H}_2\text{O}+\text{CO}_2$
But this can be easier:
\ce{CH4 + 2O2 > 2H2O + CO2}
$\ce{CH4 + 2O2 > 2H2O + CO2}$
Here you can see the main things(these are the examples from there):
\ce{H2O}  $\ce{H2O}$ 
\ce{CrO4^2}  $\ce{CrO4^2}$ 
\ce{A <> B}  $\ce{A <> B}$ 
\ce{A >[x_i] B}  $\ce{A >[x_i] B}$ 
\ce{CO2 + C > 2 CO}  $\ce{CO2 + C > 2 CO}$ 
\ce{A\bond{~}B\bond{~=}C\bond{~}D}  $\ce{A\bond{~}B\bond{~=}C\bond{~}D}$ 
Spaces are necessary
And the square drawing:
\rule[raise]{width}{height}
\rule{78pt}{.4cm}\color{red}\rule[.2cm]{24px}{2 mm}\hspace{24px}\color{blue}\rule{24px}{2mm}
$\rule{78pt}{.4cm}\color{#D61F06}\rule[.2cm]{24px}{2 mm}\hspace{24px}\color{#3D99F6}\rule{24px}{2mm}$
For more information see: 3.2. Spaces and line breaks
And the big question:
\LaTeX
Here is a cool website, where you can make equations without learning codes.
\LARGE
can be too big)You can make symbols with negative spaces, rectangles, characters.... There are two examples from my note about programming tasks:
$\color{#888888}\Large\bigodot \hspace{666200sp}\rule[3px]{1.3px}{5.5px}\hspace{289000sp}\rule[11.5px]{7.5px}{1.7px}$ $\hspace{1pt}$
$\color{#888888}\rule[4px]{14px}{2.2px}\hspace{14px}\rule{14px}{2.2px}\hspace{14px}\rule[4px]{14px}{2.2px}$
Easy Math Editor
This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.
When posting on Brilliant:
*italics*
or_italics_
**bold**
or__bold__
paragraph 1
paragraph 2
[example link](https://brilliant.org)
> This is a quote
\(
...\)
or\[
...\]
to ensure proper formatting.2 \times 3
2^{34}
a_{i1}
\frac{2}{3}
\sqrt{2}
\sum_{i=1}^3
\sin \theta
\boxed{123}
Comments
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Top NewestExcellent LaTeX formatting guide! I am saving this one...
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Thank you! I'm working on this yet
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Don't worry. I put it in my saved collection!
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Huhh! I extended it.
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I hope this is better
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@Jeff Giff Here is a new formatting guide for Radmaths !
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@Jeff Giff See what will happen if you click to the link to this guide. Delete your link's last section from there: ?from_notification=...
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And thank you!
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Red Maths LOL :)
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Its RADMaths, but...
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there you can understand it
I think he can use the rad word. FromLog in to reply
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$\color{#D61F06}\text{redmath}$ is rad. BTW this isn't important
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Great! The only one with the cases, which I once spent AN HOUR looking for :P
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Thank you!
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Now this is complete :) Maybe some codes are missing, but I think I finished it
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$\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\\[3.75pt] {\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}\\[3.75pt] \rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\\[3.75pt] {\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}\\[3.75pt] \rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\\[3.75pt] {\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}\\[3.75pt] \rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\\[3.75pt] {\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}{\color{#FFFFFF}\rule{20px}{20px}}\rule{20px}{20px}$
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$\rule{100pt}{161.8pt}$
Golden ratio
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WHA WHAAA WHAAAAAAAAAAAAAAAA! How much time do you have? I've got 30 minutes a day to update my guide lol, this one is way better. Awesome @Páll Márton  This deserves to be turned into a Latex wiki, maybe you should ask Brilliant Mathematics, Calvin Lin, or someone else.......................
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Yeah, I have a lot of time. But I think the wiki page is better. I wanted to make an example, where you should search the error, but this take a lot of time
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Yours is better than wiki page, as you have more than what the wiki has, just ask some moderator or something dude, this is good stuff
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$\LaTeX$. There you can see more codes. But you are right, because some codes are missing.
The wiki page is about onlyLog in to reply
Wait... the mod and bmod. Wrong code.
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Why? If you write only
\mod
then it won't work, but~\mod~
$~\mod~$Log in to reply
No, look $a\equiv b \mod n,a \bmod n, a\pmod n$ , mod, bmod, pmod
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a\equiv b \mod n,a \bmod n, a\pmod n
so the codes are good.Log in to reply
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$\bra{1}$ \bra{1}, for qubits
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I can't write anything. Just stop it. I don't understand your jokes. What is so funy in facepalm?
@Jeff Giff isn't annoying. Peace(and glory :D )!
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This isn't working. The space is too big :)
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Vaguely speaking, it does look like a facepalm, albeit unusual.
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Di Immortales! Did it take you 2 hours to type that, or did you copy/paste?
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copy/paste :)
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Jeff Giff isn't annoying in a Heisaidiot kind of way
More like a Leokindofway, so nothing bad about it :)
facepalm isn't funy, its funny :)
The jokes were courtesy of Leo, but they were pretty nonfunny, if that's even a word.
Happy 7.27 day!
Before you ask what 7.27 day is its today 7/27/2020, why you may ask, because a super complex number like pi has a day, why not 7.27 :)
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@Páll Márton  How do you make that box, where latex doesn't work, the one where you write your syntax, and the one where you wrote the latex commands for greeks letters as an example, your guide is very long, so i didn't find it LOL
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2.7. and 2.8. Code blocks and Formatted box :)
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Ctrl+f
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Got it, thanks!
@Páll Márton
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Yeah.
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You are welcome!
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Excellent work @Páll Márton
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Thank you! But this was a long work :)
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