[*]Left: [b]Ellipse[/b] is the projection of the 3D solid onto the xy-plane.[br][/*][*]Right: Volume between two surfaces (GREEN and BLUE)[/*][*]The region of integration is bounded by the ellipse.[br][/*][*]Used for [b]double or triple integration[/b] to compute volume between surfaces.[br][/*]

[u][color=#0000ff]https://www.geogebra.org/classic/mwunnjmk[/color][/u]