College Algebra & Trigonometry, 2018a

228 CHAPTER 4. FUNCTIONS
17) h(x) = √ (x 2 − x − 1) 3 18) h(x) = 3√ (1 − x 4 ) 2
19) h(x) =
2
√
4 − x
2
( ) 5 3
20) h(x) =−
x − 1
21) A spherical weather balloon is inflated so that the radius at time t is given
by the equation:
r = f(t) = 1 2 t +2
Assume that r is in meters and t is in seconds, with t =0corresponding to the
time the balloon begins to be inflated. If the volume of a sphere is given by the
formula:
v(r) = 4 3 πr3
Find V (f(t)) and use this to compute the time at which the volume of the balloon
is 36π m 3 .