Question

I asked this yesterday and had no replies.
The gross national product of a certain country is N(t)=t^2+3t+121 billion dollars where t is the number of years after 1990. At what percentage rate will the GNP be changing with respect to time in 1995? I got 13%, is this correct?

Answer 1

given that t=5
so GNP=161
The rate of increase of GNP is
\[\frac{dGNP}{dt}=2t+3=13\]
there fore percentage increase is
\[\frac{13}{161}100=8.0745\%\]

Answer 2

How do you get GNP=161

Answer 3

I am sorry ..... i did a mistake
GNP=t^2+3t+12=5^2+3*5+12=52

so, 13/52*100=25%

Answer 4

the problem is t^2+3t+121 not 12
i took the derivative of this equation which is 2t+3 then t(5) then I get 13.

Answer 5

then my first reply is correct ....
GNP=t^2+3t+12=5^2+3*5+12=161

so, 13/161*100=8.0745%

Answer 6

but where do you get 161

Answer 7

from the given formula ....
also given time = t= 1995-1990=5
gross national product (GNP) = t^2+3t+121 =5^2+3*5+121=161

Answer 8

ok i guess i should replace the t(5) with the original problem and the problem after I take the derivative.

Answer 9

yes ....

Answer 10

Thank You