1. (a) Derive Newton's identity k n n-r (B) (C)-(C) (-2) k r = r k n≥ k ≥r ≥ 0

Plant Growth Researchers have found that the probability P that a plant will grow to radius R can be described by the differential equation dPdR=4DRP2 where D is the density of the plants in an area. Source: Ecology. Given the initial condition P(0)=1, find a formula for P in term of R.