These formulas are meant for the latex formula renderer in inkscape 0.48
You will need some dependencies for this render extension to show,
On Linux you need, dvi2ps and pstoedit as well as latex.
On windows you need, "write what you need here"

lp1filter: \(\displaystyle\frac{1}{\frac{s}{w}+1}\)
firstorder: \(\displaystyle\frac{\frac{s}{w_{1}}+1}{\frac{s}{w_{2}}+1}\)

lp2filter: \(\displaystyle\frac{1}{\frac{s^{2}}{w^2}+\frac{2d}{w}s+1}\)
secondorder: \(\displaystyle\frac{\frac{s^{2}}{w_{1}^2}+\frac{2d_{1}}{w_{1}}s+1}{\frac{s^{2}}{w_{2}^2}+\frac{2d_{2}}{w_{2}}s+1}\)

integrator: \(\displaystyle\frac{1}{s}\)
