Increase math formula size and center images in LaTeX

[FrogPad]

Anyone good with LaTeX? (not the built in stuff (although its probably the same))

I'm trying to type a school document in $$\LaTeX$$ (using MikTeX) and everything is going pretty smooth except for a few things. How the hell do I increase the size of ALL mathematical formula.
I want all of the math in the document to become larger. So, for example if this: $$e^{ix}=\cos x + i \sin x$$ is the size in my document. How do I increase it to, let's say twice its size?
Also, if anyone knows how to center an image (I'm using the \includegraphics command) please let me know.
Thanks a billion!
Seriously $$\LaTeX$$ is awesome by the way. (on a side note) I'm hoping my skills in it will get good enough so I finally stop using Microsoft word... yuck :(

 

[Pengwuino]

Well you probably have to use the word processing programs font size changer...

 

[primal schemer]

To center an image just use the \centering command. e.g.:

\begin{figure}
\centering
\includegraphics[scale = X]{ImageName}
\caption{sdsd}
\end{figure}

PS

 

[FrogPad]

Thanks primal :) that worked like a charm.

Pengwuino, I'm using notepad. Should I use a specific $$\TeX$$ editor to change the math font?