document.write( "Question 685199: The popluation of Oregon grew from 2.8 million in 1980 to 3.42 million in 1990. Write a base-e exponential function to show how popluation depends on time. What population would be predicted for 2008? After how many years will Oregon's popluation double? \n" ); document.write( "
Algebra.Com's Answer #424467 by stanbon(75887)![]() ![]() ![]() You can put this solution on YOUR website! The popluation of Oregon grew from 2.8 million in 1980 to 3.42 million in 1990. Write a base-e exponential function to show how population depends on time. \n" ); document.write( "---- \n" ); document.write( "y = ae^(rt)\r \n" ); document.write( "\n" ); document.write( "--- \n" ); document.write( "Using (0,2.8) \n" ); document.write( "2.8 = ae^0 \n" ); document.write( "a = 2.8 \n" ); document.write( "----- \n" ); document.write( "Using (10,3.42) \n" ); document.write( "3.42 = 2.8e^(10r) \n" ); document.write( "e^(10r) = 1.22 \n" ); document.write( "10r = ln(1.22) \n" ); document.write( "r = 0.0199 \n" ); document.write( "----- \n" ); document.write( "Equation: \n" ); document.write( "y = 2.8e^(0.0199t) \n" ); document.write( "------------------------- \n" ); document.write( "What population would be predicted for 2008? \n" ); document.write( "f(8) = 2.8*e^(0.0199*8) = 3.28 million \n" ); document.write( "===========================================\r \n" ); document.write( "\n" ); document.write( "After how many years will Oregon's population double? \n" ); document.write( "It doubles when e^(0.0199t) = 2 \n" ); document.write( "0.0199t = ln(2) \n" ); document.write( "t = ln(2)/0.0199 \n" ); document.write( "t = 34.8 years \n" ); document.write( "================== \n" ); document.write( "Cheers, \n" ); document.write( "Stan H. \n" ); document.write( "---- \n" ); document.write( " |