The median weight of a boy whose age is between 0 and 36 months can be approximated by the function w(t)=8.65+1.25t0.0046t2+0.000749t3, where t is measured in months and w is measured in pounds. Use this approximation to find the following for a boy with median weight in parts a) through c) below. a) The rate of change of weight with respect to time. w(t)=