The rate of change in revenue for Under Armour from 2004 through 2009 can be modeled by dR /dt = 13.897t + 284.653 t where R is the revenue (in millions of dollars) and t is the time (in years), with t = 4 corresponding to 2004. In 2008, the revenue for Under Armour was $725.2 million. †
(a) Find a model for the revenue of Under Armour. (Round your constant term to two decimal places.) R(t) = 6.9485t2+284.653 ln(t)-311.42 Correct: Your answer is correct.
(b) Find Under Armour's revenue in 2009. (Round your answer to two decimal places.) $ million

The biologist has a second culture to examine. she knows that the population of the culture doubles every 15 minutes. after 1 hour and 15 minutes, her assistant found that 80,000 bacteria were present. a) what was the size of the initial population? b) predict the size of the culture at t=3 hours. what was the size of the population at 40 minutes? explain and justify your answers. c) create a graph of the population as a function of time. find an equation that can be used to predict the size of the population at any time t. d) examine the rate at which the bacteria culture is growing. how fast is the culture growing after 1 hour? after 1.5 hours? after 2 hours? use a time interval of h = 0.01 hours to estimate these rates. interpret these rates in terms of the context of the problem situation. how do these three rates compare?