Published online by Cambridge University Press: 17 January 2013
1. I Divide cubic equations into two varieties or species: the one, comprehending all cubic equations with three real roots; the other, all those with only one real root.
2. Let φ denote any angle whatever, and let τ = tan φ, the radius being unity: let also : then from the doctrine of angular sections we have
which being reduced to the form of an equation, is
Z3-3τZ2-3Z+τ=0.