Projective Geometry
In projective geometry, a cylinder is simply a cone whose apex is at infinity. Intuitively, if one keeps the base fixed and takes the limit as the apex goes to infinity, one obtains a cylinder, the angle of the side increasing as arctan, in the limit forming a right angle.
This is useful in the definition of degenerate conics, which require considering the cylindrical conics.
Read more about this topic: Cone
Famous quotes containing the word geometry:
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—J.G. (James Graham)