I'm new on Mathematica, I started to work with it yesterday and this software is simply amazing!
However I'm having the following trouble which I couldn't find any solution on internet (I use a linux distro):
I went to Wolfram demonstration page and I clicked on "download author code".
I opened the file: SecantAndTangentLines-author.nb
I didn't see any graph or code. Then I clicked on update thumbnail and snapshot and enable dynamics bottom
Mathematica gave me a lot of errors:
Edit: I've already solved the problem and the graph is working. However, I couldn't see where is the author code.