# Help:Formulas

There is a possibility to display mathematical or chemical formulas in the text of the articles. Characters of the Greek alphabet can be inserted as well. How to insert these useful things is described below.

## Mathematical formulas

Simple formulas can be inserted as a plain text, of course (a + b = c). But some formulas are so complicated that have to be inserted as a special piece of code.

Special tag $ is used for the complicated formulas. It allows to insert special mathematical symbols, quotations, formulas and large expressions. It uses syntax similar to LaTeX code. For example, code [itex]\sqrt{1-e^2}$ does this: $\displaystyle{ \sqrt{1-e^2} }$. As you can see, the tag $ is followed by the code of the expression and the ended by end-tag $.

Even if you can use it to create very complicated expression, this probably will not be used at WikiLectures. So this help article shows only basics of the code.

Code (inside the [itex] tag!) Preview
+ - \times \div $\displaystyle{ + - \times \div }$
\sqrt{2} \sqrt[n]{x+1} $\displaystyle{ \sqrt{2} \; \sqrt[n]{x+1} }$
< = > $\displaystyle{ \lt = \gt }$
\leftarrow \rightarrow \uparrow \downarrow $\displaystyle{ \leftarrow \rightarrow \uparrow \downarrow }$
\Leftarrow \Rightarrow \Uparrow \Downarrow $\displaystyle{ \Leftarrow \Rightarrow \Uparrow \Downarrow }$
a^2 a_2 a^2_3 a^{c+3} $\displaystyle{ a^2 \; a_2 \; a^2_3 \; a^{c+3} }$
\alpha \beta \gamma \delta \epsilon \zeta \eta \theta \iota \kappa \lambda \mu \nu \xi \pi \rho \sigma \tau \upsilon \phi \chi \psi \omega $\displaystyle{ \alpha \beta \gamma \delta \epsilon \zeta \eta \theta \iota \kappa \lambda \mu \nu \xi \pi \rho \sigma \tau \upsilon \phi \chi \psi \omega }$
\Alpha \Beta \Gamma \Delta \Epsilon \Zeta \Eta \Theta \Iota \Kappa \Lambda \Mu \Nu \Xi \Pi \Rho \Sigma \Tau \Upsilon \Phi \Chi \Psi \Omega $\displaystyle{ \Alpha \Beta \Gamma \Delta \Epsilon \Zeta \Eta \Theta \Iota \Kappa \Lambda \Mu \Nu \Xi \Pi \Rho \Sigma \Tau \Upsilon \Phi \Chi \Psi \Omega }$

## Chemical formulas

Chemical formulas can be written as a plain text (NO), text with special tags using edit buttons above the edit field (H<sub>2</sub>O → H2O).

## Greek alphabet

You can insert characters of the Greek alphabet directly in the text using these pieces of code:

Code Preview
&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;

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