


be fixed real numbers. A function f
is defined by

Suppose that for all x, we have
.
Prove that
.

A game consists of pushing a flat stone along the sequence of squares
shown above. The stone is
initially placed on square
and is given a push to the right.
When it stops on square
it is pushed again in the same
direction. This continues until the stone either stops on square
or goes beyond this square. Then the game stops.
Successive pushes of the stone are independent of one another. Each
time the stone is pushed, the probability that it will move exactly
n squares is given by
. Determine the probability that the
stone will stop exactly on square
.