Algerbra

posted by .

The U.S. population in 1990 was approximately 250 million, and the average growth
rate for the past 30 years gives a doubling time of 66 years. The above formula for the
United States then becomes
P (in millions)= 250 x 2( y-1990)/66

1.What was the approximate population of the United States in 1960?

2. What will the population of the United States be in 2025 if this
growth rate continues?

P (in millions)= 250 x 2^[( y-1990)/66]

Insert y = 1960 and y = 2025 in here.


yes i do that but I do not get a correct answer. 2025-1990=35/66=.5303
1960-1990=-30/36=-.4545
what do i do from there I know the answer for the 1960 in 182 million but I am still stuck on how they got that answer


250*2^(0.5303) = ...? (use your calculator)

And:

250 million *2^(-0.4545) = 182 million




So it is the square root -0.4545

i appreciate your help

No, it's 2 to the power -0.4545.

I think you know that:

a^n = a*a*a*... *a (n factors of a)

But here n must be a positive integer. It turns out one can "continue" the power function allowing n to take on any real value and not just a positive integer.

I know I am asking a lot of question but let say -0.4545, how exactly do you figure that out, I do not have a calucator that I can push in the numbers, I use the one on my computer, that is why I am asking.

Thank You Again For your Help

If you have the e^x (or Exp) function and the ln(x) function, then you can use that:

2^(x) = e^[x*ln(2)] Or

2^(x) = Exp[x*ln(2)]

If you have just addition multiplication and division, then you can still compute it using series expansions. I can explain that later, if necessary...

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. algebra help please

    The U.S. population in 1990 was approximately 250 million, and the average growth rate for the past 30 years gives a doubling time of 66 years. The above formula for the United States then becomes P (in millions) = 250 times 2( y-1990)/66 …
  2. math 117/algebra

    The US population 1990 was approximately 250 million, and the average growth rate for the past 30 years gives a doubling time of 66 years. The above formula for the US then becomes P(in millions) = 250 x 1(y - 1990)/66 (1) What will …
  3. Science!! Please HELP

    If a population consists of 10,000 individuals at time t=0 years (P0), and the annual growth rate (excess of births over deaths) is 3% (GR), what will the population be after 1, 15 and 100 years (n)?
  4. POPULATION

    If a population consists of 10,000 individuals at time t=0 years (P0), and the annual growth rate (excess of births over deaths) is 3% (GR), what will the population be after 1, 15 and 100 years (n)?
  5. Calculus

    The population of a region is growing exponentially. There were 40 million people in 1980 (when t=0) and 50 million people in 1990. Find an exponential model for the population (in millions of people) at any time t, in years after …
  6. Science!! Please HELP

    If a population consists of 10,000 individuals at time t=0 years (P0), and the annual growth rate (excess of births over deaths) is 3% (GR), what will the population be after 1, 15 and 100 years (n)?
  7. precal

    You can find the size of a population after t years using the formula N = No(1 + r)t where No is the initial size of the population, N is the final size of the population, r is the rate of growth or decay per time period, and t is …
  8. 6th grade Math

    I need some help figuring out how to work the word problem below. It says in 2000, the population of the United States was 280 million people. Between 1990 and 2000, the population grew by about 12%. What was the US population in 1990?
  9. Algebra 2

    According to the US Census Bureau, the population of the United States has been growing at an average rate of approximately 2% per year. The census is taken every 10 years, and the population in 1980 was estimated at 226 million people. …
  10. Algebra

    Complete the following table Growth rate is k, Doubling time is T Population Growth Rate Doubling time Country A 1.3% yr ?

More Similar Questions