SOLUTION: The worldwide number (in millions) of a particular phone sold can be approximated by the function f(x)=-871+398lnx, where x=11 corresponds to 2011.
(a) What was the number
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(a) What was the number
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Question 1190016: The worldwide number (in millions) of a particular phone sold can be approximated by the function f(x)=-871+398lnx, where x=11 corresponds to 2011.
(a) What was the number of worldwide sales for the particular phone in 2015?
(b) If the model continues to be accurate, what was the first full year in which the particular phone sales exceed 254 million?
PLEASE ANSWER A & B Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! f(4-2015)=-871+398 ln 15=206.80 million phones
254=-871+398 lnx. Isolate the ln x
1125=398 ln x
ln x=2.8266. Without rounding, raise that to the e power
x=16.889 or 17 years or 2017
check
-871+398 ln 17=256.61M which is just greater than 254M.
