I'm attracted to the tangle option because the normal latex export seems to take everything in my .org file, e.g.,

* Introduction
LaTeX is a document markup language and a document preparation system
for the TeX typesetting program.

#+BEGIN_LaTeX
\begin{eqnarray*}
\hat{f}(x) & \propto & \sum_{\nu} \frac{|F(\nu)H(\nu)|^2}{|N(\nu)|^2}  
           \frac{G(\nu)}{H(\nu)} e^{\frac{2 \pi i \nu x}{N}}\\
           & \propto & \sum_{\nu} \frac{|F(\nu)|^2}{|N(\nu)|^2} H(\nu) H^*(\nu) 
           \frac{G(\nu)}{H(\nu)} e^{\frac{2 \pi i \nu x}{N}}\\
           & \propto & \sum_{\nu} H^*(\nu) G(\nu) e^{\frac{2 \pi i \nu x}{N}}
\end{eqnarray*}
#+END_LaTeX

will result in both the * Introduction blurb as well as the stuff between the tatex "structural elements" being exported. With latex babel I can tangle and get only what I want. This is handy if I want to throw around a lot of chatter and extraneous stuff that ultimately I won't want in my final document. We might call this "annotations a la orgmode." But, yes, then I don't get the built-in orgmode latex support that comes with a regular latex export. Please advise if I'm wrong on this understanding.

On Mon, Apr 27, 2015 at 5:33 AM, Eric S Fraga <e.fraga@ucl.ac.uk> wrote:
On Sunday, 26 Apr 2015 at 19:20, Lawrence Bottorff wrote:
> I'm following the Latex howto of org-mode babel. Here's the snippet from
> the howto I've got in a separate .org file (see bottom of howto page):

[...]

> My real confusion starts when I try to tangle the babel code blocks. The
> C-c C-v t command produces two separate files just fine, a .tex and .el,
> but then if I try to Run Latex on the .tex file just by itself it gives an
> error. Here's what the org-mode tangle produces:

Why do you wish to tangle?  The LaTeX will definitely not work
standalone as it is not complete.  You can export your document to LaTeX
(C-c C-e l l) which is probably what you want?
--
: Eric S Fraga (0xFFFCF67D), Emacs 25.0.50.1, Org release_8.3beta-1062-gce4e64