Problem #75
A hemisphere of radius 1 rests on a table. There are n
hemispherical caps stacked on top of it with the equator of each
sphere resting on the surface of the one below it (the diagram below
illustrates the case n = 2). If the radii of the n
hemispherical caps vary (but the hemisphere of radius 1 remains
unchanged), what is the maximum possible height of the stack for a given
n?