1. ## Circumgyrate Surface

As uausl,write the formular of Circumgyrate Surface is not diffcult. But this problem is not easy:

Assume $l_{1}$ and $l_{2}$ are two lines that can not in one plane. and They're not uprightness. Please write the formular of the surface that $l_{2}$ circumgyrated with $l_{1}$.

thanks very much

2. Originally Posted by Xingyuan
As uausl,write the formular of Circumgyrate Surface is not diffcult. But this problem is not easy:

Assume $l_{1}$ and $l_{2}$ are two lines that can not in one plane. and They're not uprightness. Please write the formular of the surface that $l_{2}$ circumgyrated with $l_{1}$.

thanks very much
I assume that you mean a rotation-hyperboloid.

The line $l_1$ (in black) rotates around the line $l_2$ (in red) which are not in one plane and which are not perpendicular to each other.

Without any values I'm not able to give you any formula of the hyperboloid.