Jaime is blowing up a balloon. Suppose the volume(V), in cm cube, of the balloon is given by V=30t is the time in seconds since he began blowing up the balloon.
a), find a function giving the radius (r) of the balloon as a function of the volume.
b). find a function giving the radius of the balloon as a function of time.
c). when will the radius surpass 12cm?
數學! FUNCTION既問題!
2009-11-22 1:44 pm
回答 (1)
2009-11-22 4:05 pm
✔ 最佳答案
a) V = 4pr^3/3 where p = piso 3V/4p = r^3
r = (3V/4p)^(1/3)
b)
Since V = 30t
so r = [3(30t)/4p]^(1/3)
= (45t/2p)^(1/3)
c)
r^3 = 45t/2p
Put r = 12
12^3 = 45t/2p
t = 2(1728)p/45 = 241 s ( correct to 3 sig. fig.)
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