The silver blue-green coloring of the Colorado blue spruce makes it a perfect Christmas tree. For a tree farmer in Upstate New York, when a seedling is planted at time t = 0,the height of the
tree is 1foot. If h(t) is the height of the tree, in feet, at time in feet, at time t years after it is
planted, then the rate of growth is proportional to the difference between its maximum height,
10ft, and its current height and is given by
dh
3
(10 - h)
dt
20
a. Is the tree growing faster when it is 2ft or when it is 4ft? explain your reasoning.
HINT: The steepness of the curve will determine the rate of increase (2marks)