an interesting post to how google can generate equations like

http://chart.apis.google.com/chart?cht=tx&chf=bg,s,FFFFFF00&chco=AACCFF&chl=ihbarfrac{partial}{partial%20t}%20Psi(mathbf{r},,t)%20=%20hat%20H%20Psi(mathbf{r},t)

source:
http://moultano.blogspot.com/2009/11/google-can-generate-your-equations-for.html