Y by Adventure10
A solid right circular cylinder with height
and base-radius
has a solid hemisphere of radius
resting upon it. The center of the hemisphere
is on the axis of the cylinder. Let
be any point on the surface of the hemisphere and
the point on the base circle of the cylinder that is furthest from
(measuring along the surface of the combined solid). A string is stretched over the surface from
to
so as to be as short as possible. Show that if the string is not in a plane, the straight line
when produced cuts the curved surface of the cylinder.









