Hello,

Complete newbie here and have being reading for the last two days.

A question that I Googled a *lot* before asking and gave up.

I have this:

Dh :=  (a, Db, b, g) -> a*Db*sqrt(tan(b)^4/(cos(g)^4*(tan(g)+tan(b))^4)+tan(g)^4/(cos(b)^4*(tan(g)+tan(b))^4))