# MathJax

MathJax is software for typing formulas [1]. It uses the Latex style, making the source of the web-article compatible with style of a scientific journal.

MathJax logo by [1]

## Dollar

In MathJax, as in Latex, many things are controlled by dollars. Typing the sign of dollar, id est, $$\$$ $$, switches on the mathematics mode; then, the characters are interpreted as mathematical symbols or as the [[Latex]] commands. If the dollar appears again, it switches the control back to the normal typesetting. In such a way, to type some math and then some plain text, one needs at least two dollars. The results may look like this:$$\int_a^b f(x)\mathrm d x$$. Typing two dollars at once, id est,$$ \$$\$$ $$, reserves the special line for the equation. After to finish this equation, the double-dollar should be repeated again. The result may look as this'"UNIQ-MathJax2-QINU"' =='"UNIQ--h-1--QINU"'nomathjax== In [[Wo]], [[MathJax]] is supported by default. It can be desactivated with command [[nomathjax]], just type$$<\! \rm nomathjax \!>$$. After such a command, the dollars loss their usual value '"UNIQ--ref-00000002-QINU"' and are interpreted as ordinary characters; they can be typed in any amount without any special effect. In such a way, you may print so many dollars as you need. Then the MathJax can be activated again with command$$<\! \rm /nomathjax \!>\$.
After such a command, the dollars get back their normal meaning and ability to switch-on and switch-off the math mode.

Temporal suppressing of MathJax is essential at the including of some code in Latex and/or in PHP, where dollars are important.

## Numbering of formulas

The similarity with Latex appears in the numbering of formulas. The test of equation references is suggested at http://cdn.mathjax.org/mathjax/latest/test/sample-eqrefs.html [3]. Similar examples are shown below.

Here is a labeled equation$f_1(x)=\frac{x+1}{\sqrt{1-x^2}}\label{ref1}\$ it is labeled as "ref1", and here is reference to ref1: \ref{ref1}.

In the similar way, one may label another equation, $$f_2(x)={x+2\over\sqrt{1-x^2}}\label{ref2}\$$ it is labeled as "ref2", and here is reference to ref2: \ref{ref2}. The equations should be referred one by one, for example, \ref{ref1}, \ref{ref2}. Attempts to cite them both at once is interpreted as an error \ref{ref1,ref2}, and marked with red.

## Numbering of formulas, again

Sorry, there is some problem with it

The similarity with Latex appears in the numbering of formulas. The test of equation references is suggested at http://cdn.mathjax.org/mathjax/latest/test/sample-eqrefs.html [4]. Similar examples are shown below.

Here is a labeled equation$f_1(x)=\frac{x+1}{\sqrt{1-x^2}}\label{eq:ref1}$

or

$f_1(x)=\frac{x+1}{\sqrt{1-x^2}}\label{eq:ref2}$

or

$$f_1(x)=\frac{x+1}{\sqrt{1-x^2}}\label{eq:ref3}$$

or

$$f_1(x)=\frac{x+1}{\sqrt{1-x^2}}\label{eq:ref5}$$

it is labeled as "ref1", and here is reference to ref1: \eqref{eq:ref1}.

\refeq{eq:ref1}.

In the similar way, one may label another equation, $$f_2(x)={x+2\over\sqrt{1-x^2}}\label{eq:ref4}$$ it is labeled as "ref2", and here is reference to ref2: \eqref{eq:ref4}. The equations should be referred one by one, for example, \ref{ref1}, \ref{ref2}. Attempts to cite them both at once is interpreted as an error \ref{ref1,ref2}, and marked with red.

## References

1. http://www.mathjax.org/ MathJax is an open source JavaScript display engine for mathematics that works in all modern browsers.
2. With command \)<\! \rm nomathjax \!>\(, one can easy refute the widely spread concept "Dollar is always Dollar, even in Africa!"
3. http://cdn.mathjax.org/mathjax/latest/test/sample-eqrefs.html A test of Equation References.
4. http://cdn.mathjax.org/mathjax/latest/test/sample-eqrefs.html A test of Equation References.