The population of a Midwestern city decays exponentially. If the population decreased from 900,000 to 800,000 from 2003 to 2005, what will be the population in 2008?

Respuesta :

Hello.   

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Let 2003 be the zero year; then 2005 is the three year, and 2008 the 5 year.
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P = ab^x
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P(3) = ab^3 = 800000
P(0) = ab^0 = 900000

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a = 900000
Solve for "b"::
b^3 = 8/9 
b = 2/cbrt(9) 
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Equation::
P(x) = 900000^x
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Ans: P(5) = 900000


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