Motion of a particle with varying mass

Pretty simple question :), lets see who can get it hehe

A particle P increases its mass, through condensation of moisture, at a constant time rate **(m0/tau),** where **m0** is the initial mass of **P** and **tau** is a constant. The particle moves freely under gravity and is projected from O, the origin or coordinates, with a velocity whose horizontal and vertical components are U and V respectively. Show that the coordinates (x,y) of P, when its mass is m, are given by:

x = U*tau*ln(m/m0)

y=0.25g*(tau)^2(1-m^2/m0^2)+(V*tau+0.5g(tau)^2)ln(m/m0)