Hi Alan and all,
You say
> The approach we have decided to adopt is to include
> an alt tag with each equation. The equations themselves
> are images.
Long ago I applied some of this for the math on my web
page at the URL
http://www.seeingwithsound.com/vbme3.html
It isn't complete, and it is not ideal, while in some
cases I had used descriptive text rather than the exact
formula showing in the image, but you get the idea.
Best regards,
Peter Meijer
Seeing with Sound - The vOICe
http://www.seeingwithsound.com