Under certain circumstance a rumor spreads according to the equation p ( t ) = 1 1 + a e − k t where p ( t ) is the proportion of the population that has heard the rumor at time t and a and k are positive constants. [In Section 9.4 we will see that this is a reasonable equation for p ( t ).] (a) Find lim t→∞ p ( t ). (b) Find the rate of spread of the rumor. (c) Graph p for the case a= 10, k = 0.5 with 1 measured in hours. Use the graph to estimate how long it will take for 80% of the population to hear the rumor.
Under certain circumstance a rumor spreads according to the equation p ( t ) = 1 1 + a e − k t where p ( t ) is the proportion of the population that has heard the rumor at time t and a and k are positive constants. [In Section 9.4 we will see that this is a reasonable equation for p ( t ).] (a) Find lim t→∞ p ( t ). (b) Find the rate of spread of the rumor. (c) Graph p for the case a= 10, k = 0.5 with 1 measured in hours. Use the graph to estimate how long it will take for 80% of the population to hear the rumor.
Solution Summary: The author explains how to find the function's limit, and the rate of spread of the rumor.
Under certain circumstance a rumor spreads according to the equation
p
(
t
)
=
1
1
+
a
e
−
k
t
where p(t) is the proportion of the population that has heard the rumor at time t and a and k are positive constants. [In Section 9.4 we will see that this is a reasonable equation for p(t).]
(a) Find limt→∞ p(t).
(b) Find the rate of spread of the rumor.
(c) Graph p for the case a= 10, k = 0.5 with 1 measured in hours. Use the graph to estimate how long it will take for 80% of the population to hear the rumor.
Use the properties of logarithms, given that In(2) = 0.6931 and In(3) = 1.0986, to approximate the logarithm. Use a calculator to confirm your approximations. (Round your answers to four decimal places.)
(a) In(0.75)
(b) In(24)
(c) In(18)
1
(d) In
≈
2
72
Find the indefinite integral. (Remember the constant of integration.)
√tan(8x)
tan(8x) sec²(8x) dx
Chapter 3 Solutions
Bundle: Calculus: Early Transcendentals, 8th + WebAssign Printed Access Card for Stewart's Calculus: Early Transcendentals, 8th Edition, Multi-Term
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