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Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 135680: In a survey in 2000, the population of two plant species were found to be growing exponentially. Their growth is given by these equations: species A, P=2000e^0.05t and species B, P=5000e^0.02t, where t=0 in the year 2000.
Based on this information, after how many years will the population of species A be equal to the population of species B in the forest?
Click here to see answer by vleith(1977)   |
Question 135705: The count in a bacterial culture was 400 after 2 hours and 25,600 after 6 hours.
We are assuming exponential growth.
What is the rate of growth of the population of bacteria?
What was the initial population at time t = 0 hours?
Write the function that models the population n(t) after t hours.
When will the number of bacteria exceed 100,000?
Click here to see answer by jim_thompson5910(13787) |
Question 135749: This is all one problem. I'm having trouble with this: In 1997, the population of the United States was about 266 million and the exponential growth rate 0.9% per year.
a) find the exponential growth function
b) what will the population be in 2002?
d) when will the population be doubled?
Click here to see answer by stanbon(26259) |
Question 135800: Hi can you help me with this math problem?
8.) Solve the problem
An initial investment of $1000 is appreciated for 4 years in an account that earns 7% interest, compounded semiannually. Find the amount of money in the account at the end of the period.
the answer should be $1316.81
Click here to see answer by checkley77(7035) |
Question 135981: Can you please help me answer with the answer to problem for my son; then I can walk him through it. It is quite lengthy and involved.
Carbon-14 is an isotope of carbon that is formed when radiation from the sun strikes ordinary carbon dioxide in the atmosphere. Trees, which get their carbon dioxide from the air, contain small amounts of carbon-14. Once a tree is cut down, no more carbon-14 is formed, and the amount that is present begins to decay slowly. The half-life of the carbon-14 isotope is 5730 yr.
A)Find an equation that models the percentage of carbon-14 in
a sample of wood. (Consider that at time zero there is 100%
and that at time 5730 yr there is 50%.)
B)A piece of wood contains 48.37% of its original carbon-14. According to this information, approximately how long ago did the tree that it came from die? What assumptions are you making, and why is this answer approximate?
I'm sorry but I don't have the ISBN number; I only copied the page I needed from the book.
Click here to see answer by Fombitz(2113)  |
Question 136072: Could someone please show me through the steps on how to go about solving this word problem? Thank You very much!
Coyotes are one of the few species of North American animals with an expanding range. The future population of coyotes in a region of Mississippi can be modeled by the equation P=42+20ln(11t+1), where t is time in years. Use the equation to determine when the population will reach 180. (Round to the nearest tenth of a year.) The answer is 90.1 years but I don't know how they got that. Thanks again!
Click here to see answer by oscargut(682)  |
Question 136389: Solve for x:
2log(x+2)=log(3)+log(2x+1)
I do not know how to go about solving this problem at all.
Also, how do I use superscript in the text box when asking you a question? When I type it in a word document and copy/paste it into the text box, all of the superscripts turn back into regular, fully-sized numbers. Thank you.
Click here to see answer by Earlsdon(4898) |
Question 137398: if emery has $1700 to invest at %12 per year compounded monthly, how long will it be before he has $2500? if the compounding is continous, how long will it be? round the answer to three decimal places.....
the formula is A=Pe^rt for continous and A=P(1+r/n)^nt for monthly
Click here to see answer by stanbon(26259) |
Question 138525: The function P=11+44lnx represents the percentage of spam email where x is the number of years after 2002. What is the approximate percentage of spam mail in the year 2006 to the nearest tenth of a percent.Calculate to six decimals when necessary.Please explain how you obtained this answer.
Click here to see answer by ankor@dixie-net.com(6691)  |
Question 138617: Can someone help me with this problem?
by using this model P=11+44Inx, how many years will it take for the percent of spam to reach 85%?
The problem I worked before this was P=11+44Inx, I had to find the % of spam emails that would be in 4 years. The answer was 72%.
Click here to see answer by ankor@dixie-net.com(6691) |
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