4. Two horizontal frictionless rails make an angle with each other,

as shown in the figure. Each rail has a bead of mass m on it, and

the beads are connected by a spring with spring constant k and

relaxed length zero. Assume that one of the rails is positioned a

tiny distance above the other, so that the beads can pass freely

through the crossing. Find the general solution for the positions of

each mass as functions of time.