This forum has Mathjax support. Mathjax is a typesetting tool for mathematics.

It turns

(x)=(x/(n+1))*arctan(x*sqrt(sum_{i=1}^{\infty} \lambda_i)) into:

$\frac{x}{n+1}\text{arctan}(x*\sqrt(\sum_{i=1}^{\infty} \lambda_i)$

through


or

Ex(~(x=y)&F(x))|-Ax(Px<=>Fx)

into

$\begin{align}\exists x (\neg(x=y)\wedge F(x))\implies \forall x (Px \Leftrightarrow Fx)\end{align}$

through


To use Mathjax in a post, all you need to do is use to 'math' environment. This can be summoned by

Useful logical symbols are:

logical conjunction: $\wedge$ is logical disjunction: $\vee$ is negation: $\neg$ is existential quantifier: $\exists$ is universal quantifier: $\forall$ is forward implication: $\Rightarrow$ is backward implication: $\Leftarrow$ is biconditional $\Leftrightarrow$ is
see here for a long list, the far right column's 'Latex' symbols usually work

Useful mathematical symbols are

subset: $\subset$ is superset $\supset$ belongs to $\in$
fractions: $\frac{x}{y}$ is subscripts and superscripts: $x_1 ^2$ is prime: $\prime$ is sigma notation: $\sum_{i=1}^{i=n}$ is note that you can bracket an expression with {} and Mathjax will treat it as a single expression in the intended place, whereas without {} it will usually treat what you write as two expressions. EG, if you want to obtain $x^{21}$, you write rather than which gives the wrong thing $x^21$)

limits: $\lim_{n\rightarrow\infty}$ is
you can write matrices or vectors using the \bmatrix environment

1 0
0 1

can be represented as

$\begin{bmatrix}1 & 0 \\ 0 & 1 \end{bmatrix}$

which is given by


taking a new line is \\.

If you are presenting a mathematical expression not inline consider wrapping what you write with:


multi line derivations can be achieved by using \\ within the align environment.

You can make things a lot prettier than I have here with more effort, but hopefully people take notice and logic posts become more readable.