During a regular respiratory cycle, the volume of air in liters in the human lungs can be described by the function V(t) = 0.173t +0.15t^2 - 0.035t^3 where t is the time in seconds. Estimate the time in seconds from the beginning of this respiratory cycle for the lungs to fill to their maximum volume of air. a. about 3.4 seconds b. about 4.4 seconds c. about 5.4 seconds d. about 10.4 seconds

Step-by-step explanation:

Given the volume of air in liters in the human lungs described by the function V(t) = 0.173t +0.15t^2 - 0.035t^3 where t is the time in seconds,

The beginning of this respiratory cycle for the lungs to fill to their maximum volume of air occurs when dV/dt = 0

dV/dt = 0.173 + 0.3t - 3(0.035)t²

dV/dt = 0.173 + 0.3t - 0.105t²

Since dV/dt = 0

0.173 + 0.3t - 0.105t² = 0

multiply through by -1

-0.173 - 0.3t + 0.105t² = 0

0.105t² -0.3t-0.173 = 0

Factorize;

t = 0.3±√0.3²+4(0.105(0.173))/2(0.105)

t = 0.3±√0.09+0.07266/0.21

t =  0.3±√0.16266/0.21

t = 0.30±0.4033/0.21

t = 0.7033/0.21

t = 3.349secs

t ≈ 3.4secs

Hence it will take about 3.4secs for the lungs to fill to their maximum volume of air

d

step-by-step explanation:

hello and welcome!

so, when we see the words "proportional" along with a table, we need to know that we're looking numbers that divide by the same thing.

looking at this table, we simply have to do a trial and error, and divide to see which numbers have the same quotient. if you look at choice a & c, they both have equal quotients for three of the numbers, with one exception, so those can't be the answer. looking at b, there is no similarity, so that can't be it. then, we see d; if you divide all the numbers in the table, you'll see that they all divide by two, which is a proportional relationship, and our answer!

also, always remember that the x will always be the number that goes into y, and somewhere behind this table, is a formula. for this specific table, the formula would be:

since our x-value is being divided by two to get the y-value. and if they were to ask for more numbers in the series, this is the formula you would use to find them.