How can I insert two equations on separate lines in TeXShop?

[Mantaray]

I'm having the following problem in TeXShop - how can I put two equations in two separate lines?
Thus far I have something like:

\[
 p_y = s \cos \alpha \\ 
 p_x = s \sin \alpha
\]

But I still get the two on the same line..
Help would be very much appreciated

 

[Simon_Tyler]

You need to use one of the multiline environments.
The most basic of which is array (used inside \[\])
The best is probably (as long as you're using the amsmath package)

\begin{align}
 p_y &= s \cos \alpha \\ 
 p_x &= s \sin \alpha
\end{align}

where the ampersands (&) are alignment markers.
This produces
$$\begin{align}<br /> p_y &= s \cos \alpha \\ <br /> p_x &= s \sin \alpha<br /> \end{align}$$

For more details see
http://en.wikibooks.org/wiki/LaTeX/Mathematics
and
http://en.wikibooks.org/wiki/LaTeX/Advanced_Mathematics

 

[Mantaray]

Many thanks!