Gabriel's horn or Torricelli trumpet

http://dmentrard.free.fr/GEOGEBRA/Maths/gabrielhoMD.html
[url=http://dmentrard.free.fr/GEOGEBRA/Maths/gabrielhoMD.html]http://dmentrard.free.fr/GEOGEBRA/Maths/gabrielhoMD.html[/url]
– Daniel Mentrard

Information: Gabriel's horn or Torricelli trumpet