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About this Assignment SMALL BRIAN DIXON MA 241, section 009, Fall 2005 Instructor: Drew Pasteur North Carolina State University Due: Wednesday, October 19, 2005 11:03 PM EDT Description Exponential Growth Current Score: 0 out of 16.5 and Decay Question Score 1. [SCalcCC2 7.4.02.] A common inhabitant of human intestines is the bacterium Escherichia coli. A cell of this bacterium in a nutrientbroth medium divides into two cells every 20 minutes. The initial population of a culture is 60 cells. (a) Find the relative growth rate. k = (No Response)[2.08] (b) Find an expression for the number of cells after t hours. P(t) = (No Response) [60*exp(ln(8)*t)] (c) Find the number of cells after 8 hours. (No Response)[1.00663296] billion cells (d) Find the rate of growth after 8 hours. (No Response)[2.09323439424814] billion cells per hour (e) When will the population reach 20000 cells? (No Response)[2.79] h pts subs 1 /1 /20 2 /1 /20 3 /1 /20 4 /1 /20 5 /1 /20 Notes pts subs 1 /1 /20 2 /1 /20 3 /1 /20 4 /1 /20 5 /1 /20 /0. 6 /20 5 Notes 2. [SCalcCC2 7.4.06.] The table gives the population of the United States, in millions, for the years 1900  2000. (a) Use the exponential model and the census figures for 1900 and 1910 to predict the population in 2000. (No Response)[514] million What was the actual population in 2000? (No Response)[275] million (b) Use the exponential model and the census figures for 1980 and 1990 to predict the population in 2000. (No Response)[275] million Use this model to predict the population in the year 2010. (No Response)[303] million Use this model to predict the population in the year 2020. (No Response)[334] million (c) Draw a graph showing both of the exponential functions in parts (a) and (b) together with a plot of the actual population. (Do this on paper. Your teacher may ask you to turn in this work.) Are these models reasonable ones? (_) (_) Model (a) and Model (b) are both accurate (_) (_) Model (a) is accurate and Model (b) is not (_) (o) Model (a) is not accurate but Model (b) is accurate (_) (_) Neither Model (a) nor Model (b) are accurate 3. [SCalcCC2 7.4.08.] Bismuth210 has a halflife of 5.0 days.
pts subs 1 /1 /20 2 /1 /20 3 /1 /20 Notes (a) A sample originally has a mass of 800 mg. Find a formula for the mass remaining after t days. y(t) = (No Response) [800*exp((ln(2)*t)/(5))] (b) Find the mass remaining after 10 days. (No Response)[200] mg (c) When is the mass reduced to 1 mg? (No Response)[48.2] days (d) Sketch the graph of the mass function. (Do this on paper. Your teacher may ask you to turn in this work.) pts subs 1 /3 /20 Notes 4. [SCalcCC2 7.4.12.] A curve passes through the point (0,4) and has the property that the slope of the curve at every point P is twice the ycoordinate of P. What is the equation of the curve? y(x) = (No Response) [4*exp(2*x)] Home My Assignments ...
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This note was uploaded on 10/21/2009 for the course MATH MA241 taught by Professor Hubbard during the Spring '09 term at N.C. Central.
 Spring '09
 Hubbard
 Calculus

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