<PRE><B>Question 91591</B>
Thus we may represent the population size by the exponential model A(t) = 180e^0.013t, where t is the number of years since 1960 and A(t) is the population in millions. In what year will the population of the United States exceed one billion? 
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180e^0.013t = 10^9
e^0.013t = 10^9/180
Take the natural log of both sides to get:
0.013t ln(10^9)-ln(180)
t = [9ln(10)-ln(180)]/0.013
t = 1086.98
The year this will happen is 1960 + 1086.98 = 3047
Cheers,
Stan H.</PRE>