# Use of the Ruby Module with MathML

## William F. Hammond

This is an XHTML document that uses the MathML and Ruby extensions of basic XHTML markup.

The square of x is entered here using MathML: ${x}^{2}$   [If you see this text, your browser needs updating in order to handle one or both of CSS and the XHTML Ruby module.]-- TeX source: "x^2".

Here is a displayed form of the Weierstrass infinite product expansion of the gamma function.

${\int }_{0}^{\infty }{t}^{x}{e}^{\mathrm{-t}}\frac{\mathrm{dt}}{t}=\frac{1}{x}{\prod }_{k=1}^{\infty }\frac{{\left(1+\frac{1}{k}\right)}^{x}}{\left(1+\frac{x}{k}\right)}$

[If the MathML markup above does not render in your browser, consult this image or decipher the following equivalent pseudo-TeX source:
\int_0^{\infty} t^x e^{-t} dt/t =
(1/x) \prod_{k=1}^{\infty} \frac{(1 + 1/k)^x}{1 + x/k} ]

This web page is offered as an example of a fully functioning XHTML 1.1 plus MathML 2.0 document that is both safe and usable in a wide array of legacy web browsers such as NetScape 4.5 and lynx 2.8 (rel 2).