7. The silvery blue-green coloring of the Colorado spruce makes it a perfect Christmas tree. For a tree farmer in Indiana, when a seedling is planted, at time t =0, the height of the tree is 1 foot. If h(t) is the height of the tree, in feet, at time t years after it is planted, then the rate of growth is proportional to the difference between its maximum height, 10 feet, and its current height and is given by dh - 3 (10-h). 1 20 a.) Is the tree growing faster when it is 2 feet high or when it is 4 feet high? Explain your reasoning. 20 ( 102 ) 20 ( 10- 4 ) = 24 18 = 9 20 = 20 .. it is growing faster at 2 feet high b.) Find dt 2 in terms of h. Use this expression to explain why the graph of the solution curve is concave down. c.) Find an equation of the tangent line to the graph of h at the point where - 0. Use the tangent line to approximate the height of the tree at t = 1 year. Is the estimate an overestimate or an underestimate? Explain your reasoning. d.) Find the particular solution to this differential equation with initial value h(0) = 1. e.) If a tree is harvested when its height is 8 feet, at what time t will a blue spruce be ready to sell