inline equations

Hi List,

If I have an inline equation, for example:

"The movement of nodes is calculated with the general equation: Δx =
FmΔt where Δx is the incremental displacement vector, F is the driving
force vector, m is the mobility and Δt is the time increment."

I'm unclear as to the markup I should be using within the XML.

F, m and dt being variables should be wrapped in <varname>? The
synopsis for this element points its application more toward
programming. Is it still appropriate?

What about the equation? Δx = FmΔt. As it's not an image, I can't use
<inlineequation> because there would be no graphic element. Is there a
better way?

Thanks,
Aidan