A rocket was launched and its height, h, in metres, above the ground after time, t, in seconds, is represented by h = 11 + 10t - 22. For how many seconds was
the rocket in the air?
a)
about 6.64 s
b) about 6.27 s
c) about 5.93 s
d) about 7.35 s

Let f (x) = x e8x. find a formula for the nth derivative of f, where n is any positive integer. use x and n in your answer if needed. f (n)(x) =

Lucy is a dress maker. she sews \dfrac47 7 4 of a dress in \dfrac34 4 3 hour. lucy sews at a constant rate. at this rate, how many dresses does lucy sew in one hour? include fractions of dresses if applicable

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/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 14 ft high? (round your answer to two decimal places.) ft/min