Skip to main content
7 of 7
edited body
Jap88
  • 431
  • 3
  • 7

Is the developable surface between two conic sections, not in the same plane, algebraic?

Consider two conic sections located in non-parallel planes in $\mathfrak{R}^3$ and parameterized as $\mathbf{P}_1(t)$ and $\mathbf{P}_2(t)$. Consider the ruled surface: $\mathbf{R}(s,t)=(1-s)\mathbf{P}_1(t)+s\mathbf{P}_2(t)$ that "interpolates" the two curves. Are there always reparameterizations of $\mathbf{P}_1(t)$ and $\mathbf{P}_2(t)$ such that the ruled surface $\mathbf{R}(s,t)$ becomes a developable surface? In addition, are there corresponding rational parameterizations of the conic sections for this (if it exists) developable surface? Finally, and independently, is such a surface algebraic?

Jap88
  • 431
  • 3
  • 7