multi-line equation in RMarkdown

Question

I am trying to create a multi-line equation in RMarkdown. I have tried the following code, extracted from http://www.rstudio.com/ide/docs/authoring/using_markdown_equations,

$$
\begin{aligned}
  \dot{x} & = \sigma(y-x) \\
  \dot{y} & = \rho x- y - xz 
\end{aligned}
$$

however the knitred HTML document gives a single-line equation:

Cyanite

Answer 1

This code produced 2 HTML lines, as desired, when cut and paste into RStudio in Windows 7 with knitr. If the second slash at the end of the 3rd line was removed, it produced the result shown in example.

Matias

Do you mean as follows: $$ \begin{aligned} \dot{x} & = \sigma(y-x) \ \dot{y} & = \rho x- y - xz \end{aligned} $$ because if so, I still get the same result as above. I also have Windows 7, R Studio 0.98.484 and I am using R version 3.0.2 (32-bit) – Cyanite

With R v3.0.2 (64-bit), Windows 7, RStudio 0.98.490 & knitr v1.5, when the code you provided above was copied and pasted into RStudio with no changes, it produced two lines of equations. Also worked properly when code was typed in. As a test, when the 2nd backslash was deleted at the end of the 3rd line of code (\dot{x} & = \sigma(y-x) \), it produced the single line equation you provided as an example. – Matias

$$\begin{eqnarray} a^2 + b^2 &=& c^2 \\ &=& 5 \end{eqnarray}$$ works in my environment. – Disbar

Answer 2

It's now a decade since this question was asked, but I'm having good luck with:

$$
\begin{split}
  \dot{x} & = \sigma(y-x) \\
  \dot{y} & = \rho x- y - xz 
\end{split}
$$

Within split, the locations demarcated by & will be aligned.

Solution from @Castel:

Using split:

This is especially useful for derivations:

$$
\begin{split}
x & = \int_{\tau_0}^{\tau_n}\tau^{-\alpha}\; d\tau \\
  & = \frac{\tau_0^{1-\alpha}-\tau_n^{1-\alpha}}{a-1}
\end{split}
$$

Palawan

Answer 3

I'm using markdown with Logseq and in this environment simply entering $$ \dot{x} = \sigma(y-x) \\ \dot{y} = \rho x- y - xz $$, allowed me to enter multi-line equations. Note the I removed the begin and end of the original message and also the &'s.

Whitehouse