Math Help - Constant curvature and constant torsion

1. Constant curvature and constant torsion

Describe all curves in $\mathbb{R}^3$ with constant curvature $\kappa (s) = K > 0$ and constant torsion $\tau (s) = T$.
I know the solution is a helix, but it's proving it that's the hard part.

So the first thing I did was use the Frenet Equations,

$\vec{n}'(t) = - \kappa \vec{t} + \tau \vec{b}$

Differentiating we get:

$\vec{n}''(t) = - \kappa^2 \vec{n} - \tau^2 \vec{n}$

$\vec{n}''(t) = - \underbrace{[\kappa^2 + \tau^2]}_{\omega ^2} \vec{n}$

The solution to this ODE is

$\vec{n}(t) = \vec{a} \sin (\omega t) + \vec{b} \cos (\omega t)$

Now I can integrate twice to get the parametrisation, but how do I solve for the constant vectors $\vec{a}$ and stuff?

2. Re: Constant curvature and constant torsion

you don't have to compute anything about the constant vectors; any value they assume will describe such a curve, and vice versa.