Question

The population of a region is growing exponentially. There were 40 million people in 1990 (t = 0) and 70 million in 2000. Find an expression for the population at any time t, in years. Use the general exponential function and remember to use exact values.. . P(t)= (in millions). . - What population would you predict for the year 2010?. . - What is the doubling time? (Round your answer to one decimal place.)

Answer 1

Now to find the general exponential function, we need to find out some information. P(t)= Po x R^t Where: P= total population Po=initial population R= rate t= no of years after 1990

We have the current info: P= 70 000 000 Po= 40 000 000 R=? t= 2000-1990=10years
Now we can form the equation: P (t)= 40 000x (1.05755705)^t

Now that you got your equation, you can sub in t=20 (2010-1990) to find population in 2010.

The amount of years it would it for population to double. Look at the words 'population and double'. These indicate the initial population multiplied by 2. So P (t)= 40 000 000 x 2 =80 000 000 Sub that into the equation you found.