### Learned from here

Use \mathbf in math mode. e.g.

\mu v.s. \mathbf\mu:

$\mu \;\;\; \mathbf \mu$

One drawback of \mathbf: Its not in italics.

a v.s. \mathbf a:

$a \;\;\; \mathbf a$

If you have the AMS math package (\usepackage{amssymb,amsmath}), \boldsymbol puts things in bold italics.

\mu v.s. \mathbf\mu v.s. \boldsymbol\mu

$\mu \;\;\; \mathbf \mu \;\;\; \boldsymbol \mu$

a v.s. \mathbf a versus \boldsymbol a:

$a \;\;\; \mathbf a\;\;\; \boldsymbol a$

### Learned from here

LaTeX: \headheight is too small

You never know what you will meet when you use LaTeX, luckily, we can search Google or Yahoo to find the answer. However, it cannot help all the times. There is a problem you may come across using package fancyhdr:

We now make it that large for the rest of the document. It was not easy to find the answer via either Google or Yahoo. Here is the solution. Insert

in the preamble, i.e. before \begin{document}.

Tips:

• \headheight defines the height of the header.
• \setlength{len-cmd}{length}. The \setlength command is used to set the value of a length command, len-cmd, which is specified as the first argument. The length argument can be expressed in any terms of length LaTeX understands, i.e., inches (in), millimeters (mm), points (pt), etc.

### Learned from here

How to Activate \subsubsubsection in LaTeX?

The equivalent to \subsubsubsection is \paragraph. To have that numbered simply use:

then: