Hey guys its Heimdallr. As you know this forum has added a math plugin. This is largely impart due to @sgtawesomesauce and I feeling it will be useful especially for me coming up soon!
**So without further a due I have reformatted a guide of stack exchange to display correctly here (top google result): (CREDIT GIVEN BELOW) **

To see how any formula was written in any question or answer, including this one, rightclick on the expression it and choose “Show Math As > TeX Commands”. (When you do this, the ‘$’ will not display. Make sure you add these. See the next point.)

For inline formulas, enclose the formula in
$...$
. For displayed formulas, use$...$
.
These render differently. For example, type
$\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}$
to show \sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6} (which is inline mode) or type $$ \sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6} $$ (which is display mode).
\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6} 
For Greek letters , use
\alpha
,\beta
, …,\omega
: \alpha, \beta, … \omega. For uppercase, use\Gamma
,\Delta
, …,\Omega
: \Gamma, \Delta, …, \Omega. 
For superscripts and subscripts , use
^
and_
. For example,x_i^2
: x_i^2,\log_2 x
: \log_2 x. 
Groups . Superscripts, subscripts, and other operations apply only to the next “group”. A “group” is either a single symbol, or any formula surrounded by curly braces
{
…}
. If you do10^10
, you will get a surprise: 10^10. But10^{10}
gives what you probably wanted: 10^{10}. Use curly braces to delimit a formula to which a superscript or subscript applies:x^5^6
is an error;{x^y}^z
is {x^y}^z, andx^{y^z}
is x^{y^z}. Observe the difference betweenx_i^2
x_i^2 andx_{i^2}
x_{i^2}. 
Parentheses Ordinary symbols
()[]
make parentheses and brackets (2+3)[4+4]. Use\{
and\}
for curly braces \{\}.These do not scale with the formula in between, so if you write(\frac{\sqrt x}{y^3})
the parentheses will be too small: (\frac{\sqrt x}{y^3}). Using\left(
…\right)
will make the sizes adjust automatically to the formula they enclose:\left(\frac{\sqrt x}{y^3}\right)
is \left(\frac{\sqrt x}{y^3}\right).\left
and\right
apply to all the following sorts of parentheses:(
and)
(x),[
and]
[x],\{
and\}
\{ x \},
x,\vert
\vert x \vert,\Vert
\Vert x \Vert,\langle
and\rangle
\langle x \rangle,\lceil
and\rceil
\lceil x \rceil, and\lfloor
and\rfloor
\lfloor x \rfloor.\middle
can be used to add additional dividers. There are also invisible parentheses, denoted by.
:\left.\frac12\right\rbrace
is \left.\frac12\right\rbrace.If manual size adjustments are required:\Biggl(\biggl(\Bigl(\bigl((x)\bigr)\Bigr)\biggr)\Biggr)
gives \Biggl(\biggl(\Bigl(\bigl((x)\bigr)\Bigr)\biggr)\Biggr). 
Sums and integrals
\sum
and\int
; the subscript is the lower limit and the superscript is the upper limit, so for example\sum_1^n
\sum_1^n. Don’t forget{
…}
if the limits are more than a single symbol. For example,\sum_{i=0}^\infty i^2
is \sum_{i=0}^\infty i^2. Similarly,\prod
\prod,\int
\int,\bigcup
\bigcup,\bigcap
\bigcap,\iint
\iint,\iiint
\iiint,\idotsint
\idotsint. 
Fractions There are three ways to make these.
\frac ab
applies to the next two groups, and produces \frac ab; for more complicated numerators and denominators use{
…}
:\frac{a+1}{b+1}
is \frac{a+1}{b+1}. If the numerator and denominator are complicated, you may prefer\over
, which splits up the group that it is in:{a+1\over b+1}
is {a+1\over b+1}. Using\cfrac{a}{b}
command is useful for continued fractions \cfrac{a}{b}, more details for which are given in this subarticle. 
Fonts
 Use
\mathbb
or\Bbb
for “blackboard bold”: \mathbb{CHNQRZ}.  Use
\mathbf
for boldface: \mathbf{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathbf{abcdefghijklmnopqrstuvwxyz}.  Use
\mathit
for italics: \mathit{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathit{abcdefghijklmnopqrstuvwxyz}.  Use
\pmb
for boldfaced italics: \pmb{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \pmb{abcdefghijklmnopqrstuvwxyz}.  Use
\mathtt
for “typewriter” font: \mathtt{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathtt{abcdefghijklmnopqrstuvwxyz}.  Use
\mathrm
for roman font: \mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathrm{abcdefghijklmnopqrstuvwxyz}.  Use
\mathsf
for sansserif font: \mathsf{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathsf{abcdefghijklmnopqrstuvwxyz}.  Use
\mathcal
for “calligraphic” letters: \mathcal{ ABCDEFGHIJKLMNOPQRSTUVWXYZ}  Use
\mathscr
for script letters: \mathscr{ABCDEFGHIJKLMNOPQRSTUVWXYZ}  Use
\mathfrak
for “Fraktur” (old German style) letters: \mathfrak{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathfrak{abcdefghijklmnopqrstuvwxyz}.

Radical signs Use
sqrt
, which adjusts to the size of its argument:\sqrt{x^3}
\sqrt{x^3};\sqrt[3]{\frac xy}
\sqrt[3]{\frac xy}. For complicated expressions, consider using{...}^{1/2}
instead. 
Some special functions such as “lim”, “sin”, “max”, “ln”, and so on are normally set in roman font instead of italic font. Use
\lim
,\sin
, etc. to make these:\sin x
\sin x, notsin x
sin x. Use subscripts to attach a notation to\lim
:\lim_{x\to 0}
$$\lim_{x\to 0}$$ 
There are a very large number of special symbols and notations , too many to list here; see this shorter listing, or this exhaustive listing. Some of the most common include:

\lt \gt \le \leq \leqq \leqslant \ge \geq \geqq \geqslant \neq
\lt\, \gt\, \le\, \leq\, \leqq\, \leqslant\, \ge\, \geq\, \geqq\, \geqslant\, \neq. You can use\not
to put a slash through almost anything:\not\lt
\not\lt but it often looks bad. 
\times \div \pm \mp
\times\, \div\, \pm\, \mp.\cdot
is a centered dot: x\cdot y 
\cup \cap \setminus \subset \subseteq \subsetneq \supset \in \notin \emptyset \varnothing
\cup\, \cap\, \setminus\, \subset\, \subseteq \,\subsetneq \,\supset\, \in\, \notin\, \emptyset\, \varnothing 
{n+1 \choose 2k}
or\binom{n+1}{2k}
{n+1 \choose 2k} 
\to \rightarrow \leftarrow \Rightarrow \Leftarrow \mapsto
\to\, \rightarrow\, \leftarrow\, \Rightarrow\, \Leftarrow\, \mapsto 
\land \lor \lnot \forall \exists \top \bot \vdash \vDash
\land\, \lor\, \lnot\, \forall\, \exists\, \top\, \bot\, \vdash\, \vDash 
\star \ast \oplus \circ \bullet
\star\, \ast\, \oplus\, \circ\, \bullet 
\approx \sim \simeq \cong \equiv \prec \lhd \therefore
\approx\, \sim \, \simeq\, \cong\, \equiv\, \prec\, \lhd\, \therefore 
\infty \aleph_0
\infty\, \aleph_0\nabla \partial
\nabla\, \partial\Im \Re
\Im\, \Re  For modular equivalence, use
\pmod
like this:a\equiv b\pmod n
a\equiv b\pmod n. 
\ldots
is the dots in a_1, a_2, \ldots ,a_n\cdots
is the dots in a_1+a_2+\cdots+a_n  Some Greek letters have variant forms:
\epsilon \varepsilon
\epsilon\, \varepsilon,\phi \varphi
\phi\, \varphi, and others. Script lowercase l is\ell
\ell.Detexify lets you draw a symbol on a web page and then lists the \TeX symbols that seem to resemble it. These are not guaranteed to work in MathJax but are a good place to start. To check that a command is supported, note that MathJax.org maintains a list of currently supported \LaTeX commands, and one can also check Dr. Carol JVF Burns’s page of \TeX Commands Available in MathJax.

Spaces MathJax usually decides for itself how to space formulas, using a complex set of rules. Putting extra literal spaces into formulas will not change the amount of space MathJax puts in:
a␣b
anda␣␣␣␣b
are both a b. To add more space, use\,
for a thin space a\,b;\;
for a wider space a\;b.\quad
and\qquad
are large spaces: a\quad b, a\qquad b.To set plain text, use\text{…}
: \{x\in s\mid x\text{ is extra large}\}. You can nest$…$
inside of\text{…}
. 
Accents and diacritical marks Use
\hat
for a single symbol \hat x,\widehat
for a larger formula \widehat{xy}. If you make it too wide, it will look silly. Similarly, there are\bar
\bar x and\overline
\overline{xyz}, and\vec
\vec x and\overrightarrow
\overrightarrow{xy} and\overleftrightarrow
\overleftrightarrow{xy}. For dots, as in \frac d{dx}x\dot x = \dot x^2 + x\ddot x, use\dot
and\ddot
. 
Special characters used for MathJax interpreting can be escaped using the
\
character:\$
\$,\{
\{,\_
\_, etc. If you want\
itself, you should use\backslash
\backslash, because\\
is for a new line.
Credit source: https://math.meta.stackexchange.com/questions/5020/mathjaxbasictutorialandquickreference
Please thank those guys for writing something so nicely it was easy to copy over minus the formatting.
Found the user
Please thank Mr. Mark Dominus @ stack exchange (User: MJD)