The average height of the tree after 2 years is 3 feet, and after 6 years the height of the tree is 15 feet. Assume that the annual growth of the tree is linear for 2≤t≤25.
(a) Find the annual rate of change of the height of the tree in feet per year.
(b) Find a function for the height h of the tree in feet as a function of time t in years.
(c) Find the domain of the function from part (b). Enter in interval notation.
(d) How tall will the tree be after 11 years?
(e) After how many years will the tree be 21 feet tall? Round your answer to two decimal places.