MathDB

3

Part of 1989 Cono Sur Olympiad

Problems(2)

F(1998)

Source: Cono Sur Olympiad, Uruguay 1989, Problem#3

5/14/2006
A number pp is perfectperfect if the sum of its divisors, except pp is pp. Let ff be a function such that: f(n)=0f(n)=0, if n is perfect f(n)=0f(n)=0, if the last digit of n is 4 f(a.b)=f(a)+f(b)f(a.b)=f(a)+f(b) Find f(1998)f(1998)
function
Cuboid

Source: Cono Sur Olympiad, Uruguay 1989, Problem#6

5/14/2006
Show that reducing the dimensions of a cuboid we can't get another cuboid with half the volume and half the surface.
probabilityinequalities