title: HelloThere This is a TiddlyWiki plugin for mathematical typesetting based on KaTeX from Khan Academy. It is completely self-contained, and doesn't need an Internet connection in order to work. It works both in the browser and under Node.js. ! Installation To add the plugin to your own TiddlyWiki5, just drag this link to the browser window: [[$:/plugins/tiddlywiki/katex]] ! Using KaTeX The usual way to include ~LaTeX is to use `$$`, as shown in the examples below. The underlying KaTeX widget is provided under the name `<$latex>` and is also available under the alias `<$katex>`. It's better to use the generic `<$latex>` name unless you are running multiple ~LaTeX plugins and wish to specifically target KaTeX. ! Examples These examples are taken from http://khan.github.io/KaTeX/ !! Example 1 ``` $$\displaystyle f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi$$ ``` $$\displaystyle f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi$$ !! Example 2 ``` $$\displaystyle \frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\cdots} } } }$$ ``` $$\displaystyle \frac{1}{\Bigl(\sqrt{\phi \sqrt{5}}-\phi\Bigr) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\cdots} } } }$$ !! Example 3 Use a wrapper element with the class `katex-display` to render math in display mode, centred on a single line in display style. ```
$$\displaystyle \left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right)$$
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$$\displaystyle \left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right)$$
!! Example 4 ``` $$\displaystyle 1 + \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \quad\quad \text{for }\lvert q\rvert<1.$$ ``` $$\displaystyle 1 + \frac{q^2}{(1-q)}+\frac{q^6}{(1-q)(1-q^2)}+\cdots = \prod_{j=0}^{\infty}\frac{1}{(1-q^{5j+2})(1-q^{5j+3})}, \quad\quad \text{for }\lvert q\rvert<1.$$ !! Widget Example For more flexibility the KaTeX widget can also be used via the full widget syntax: ``` <$latex text="\displaystyle f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi"> ``` <$latex text="\displaystyle f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi"> ! Error Handling An warning message is displayed if KaTeX detects a problem with the ~LaTeX syntax. For example: ``` $$\displaystyle f(x) = \int_{-\infty}^\infinity\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi$$ ``` $$\displaystyle f(x) = \int_{-\infty}^\infinity\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi$$