[chriswarbo]

> I never really thought that rational trig was worth all the effort - regular math seems to have plenty of utility even if you think it is built on shaky philosophical foundations

For those familiar with "normal" (irrational?) trig, it's certainly an extra effort to learn, and may hinder communication, which gives a poor cost/benefit ratio.

For those unfamiliar with "normal" trig (e.g. not reaching that stage in school, or having later forgot it all), then rational trig certainly seems easier to learn and understand. I also like the way it generalises, e.g. to hyperbolic space (relativity), by simply changing the dot-product.