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| Question 1035108:  between the start of 2005 and the end of 2009, the number of Facebook users can be modelled by the exponent equation u=0.43*(3.17)^t, where u is the number of users in millions nd t is the number of years since 2004 (1<=t<6)
 How do I find the year in which the exponential model predicts that the number of users would first reach 200 million?   (I know that the 1 year since 2004, the number of Facebook users is 1.4 million)
 Thanks for your help
 Answer by jorel1380(3719)
      (Show Source): 
You can put this solution on YOUR website! If u is the number of Facebook users in millions, and u=.43*(3.17)^t, where t is the number of years since 2004, then: 200=.43*(3.17)^t
 465.12=3.17^t
 log 465.12=log 3.17^t
 log 465.12=t log 3.17
 t=log 465.12/log 3.17=5.32385131974 years after 2004 that the amount of Facebook users will reach 200 million. ☺☺☺☺
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