Annual U.S. exports to the country in the years 1995 through 2003 could be approximated by the following function, where t represents time in years since 1995. At what rate was this number increasing in 2000?
I(t)=0.6t^2-1.6t+19 ;(0

Question

Annual U.S. exports to the country in the years 1995 through 2003 could be approximated by the following function, where t represents time in years since 1995. At what rate was this number increasing in 2000?
I(t)=0.6t^2-1.6t+19   ;(0<orequalto x <orequalto 8)
$________billion people per year  ?

anonymous · Answer

Take the general derivative and then plug in for 'x' (in this case, the year 2000 equates to '5' for your domain)

anonymous · Answer

im getting -1 and its saying that that is not correct ;/

anonymous · Answer

Well it's asking for the rate, so it's going to be the slope of the line tangent at that point in time. What did you do after you took the derivative?

anonymous · Answer

found (3x-40)/(25) as the derivative then entered in 5 for x and solved

anonymous · Answer

what should i have done instead?

anonymous · Answer

Well, you took the derivative incorrectly. For the 0.6t^2 term, it's 2(0.6)t^(2-1), for the -1.6t term it's just -1.6, and for the 19 term it's just 0. So your derivative will be 1.2t - 1.6

anonymous · Answer

oopes  thank you very much

anonymous · Answer

No offense but your derivative was really, really off, so I think you should review how to take derivatives more before you continue these problems

anonymous · Answer

okay thank you very much