I have a large adjacency matrix in LyX.
How can I rotate it to fit the page?
Alternative: you see that the commands such as the \begin{landscape}...\end{landscape} are not interpreted as commands in Lyx. How to type them in Lyx?

I have a large adjacency matrix in LyX.
How can I rotate it to fit the page?
Alternative: you see that the commands such as the \begin{landscape}...\end{landscape} are not interpreted as commands in Lyx. How to type them in Lyx?

Right-click on "Float: Table", click on "Settings", and check "Rotate sideways".
To insert custom LaTeX code in LyX (where you mention \begin{landscape}), go to Insert > TeX Code (ctrl + L on Ubuntu). This is referred to as "ERT".
The bottom page in the top picture (big table going over margins in sideways) is made with Lyx's option: click Float: Table, click on Settings and check Rotate sideways as instructed by scottkosty.
However I was not able to align the table properly with the default method so I ended up to the below method to manually specify the size that corresponds to the top page in the top picture.
P.s. If you know how to encapsulate the handwritten code and the table block nicely in Lyx in its GUI, please let me know. This curiosity moved here.
\begin{landscape}...\end{landscape}in Lyx that it would interpret it as a command, see the photo. – hhh Mar 13 '16 at 21:34