Update 009.md

book/syntax_exercises/009.md

@@ -72,13 +72,55 @@ The displacement can be found using the equation $s = v \cdot t$.
 
 10. Test your understanding by adding a new equation of your choice, ideally one that requires many LaTex symbols!
 
-11. When you are ready, commit your changes to the repository by clicking on the green `Commit changes` button.
 
-12. Add a commit message.
+## Adding colours to equations
 
-13. To see your changes, go to {octicon}`play` `Actions` - The most recent workflow run `overview.md / the commit message of the commit you just made` - Wait for it to finish - In the summary, click on the link of your book shown in the table `Branches deployed` and under `Primary book at root` (getting bored of waiting? There'll be exercising on doing this locally which prevents you from waiting).
+11. The TeachBooks template includes the `sphinx-named-colors` extension, which lets you add colours to parts of your equations using LaTeX. Look at the [CSS named colours](https://developer.mozilla.org/en-US/docs/Web/CSS/named-color) to explore the possible colour options.
 
-14. Do you see your change? If you don't see it click `CTRL`+`F5`/`Control`+`F5`to refresh the page.
+12. Colours are added to equations using `\namedcolour{...}`, replacing `namedcolour` with the colour of choice. Test this out with the examples in the table below:
+
+::::{list-table}
+:widths: auto
+:header-rows: 1
+   * - Color
+     - $\LaTeX$ Code
+     - Result
+   * - olive
+     - `\olive{\int_a^bf(x)dx}`
+     - $\olive{\int_a^bf(x)dx}$
+   * - hotpink
+     - `1.\hotpink{\mathbf{49}}`
+     - $1.\hotpink{\mathbf{49}}$
+   * - darkturquoise
+     - `\dfrac{\darkturquoise{\partial}f}{\darkturquoise{\partial}x}`
+     - $\dfrac{\darkturquoise{\partial}f}{\darkturquoise{\partial}x}$
+   * - onlylight
+     - `\onlylight{\LaTeX}`
+     - $\onlylight{\LaTeX}$
+   * - lightanddark
+     - `\lightanddark{\sum}_{n=1}^\infty`
+     - $\lightanddark{\sum}_{n=1}^\infty$
+::::
+
+
+13. For colours with hyphens we use need to use the class-based command `\class{named-colour}{...}. Replicate the code below:
+
+```md
+$$ \class{hyphen-color}{\sum}_{n=1}^\infty a_n $$
+```
+14. Test your understanding by creating a block equation where each term is a different colour!
+
+```{tip}
+This is especially helpful for highlighting changes between equations or focusing attention on specific terms — great for teaching, too!
+```
+
+15. When you are ready, commit your changes to the repository by clicking on the green `Commit changes` button.
+
+16. Add a commit message.
+
+17. To see your changes, go to {octicon}`play` `Actions` - The most recent workflow run `overview.md / the commit message of the commit you just made` - Wait for it to finish - In the summary, click on the link of your book shown in the table `Branches deployed` and under `Primary book at root` (getting bored of waiting? There'll be exercising on doing this locally which prevents you from waiting).
+
+18. Do you see your change? If you don't see it click `CTRL`+`F5`/`Control`+`F5`to refresh the page.
 
 
 ```{admonition} Check your understanding