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CONICAL SPIRAL OF PIRONDINI



 
Curve studied by Pirondini in 1897.
Geminiano Pirondini (1857 - 1914): Italian mathematician.

A conical spiral of Pirondini is a curve traced on a cone that intersects the generatrices at a constant angle.

Do not mistake it for a helix (constant angle with respect to a fixed direction), nor a rhumb line, but these three notions coincide in the case of a cone of revolution to give the curve named conical helix (and not conical spiral!).

Do not mistake it either for the pseudospirals of Pirondini.
 
 
 
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© Robert FERRÉOL  2018