7) Gravel is being dumped from a conveyor belt at a rate of 25 t3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. How fast is the height of the pile increasing when the pile is 10 ft high? Give your answer correct to three decimal places.

8) Iff(x) +x^2[f(x)]^3 = 30 andf(1) = 3, findf '(1).