Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 1153303: I need help understanding how my professor did this problem and how he got this answer thank you!
Determine the product.
(2.14 x 10^4) (2.07 x 10^-7)
2.14 x 2.05 x 10^4 x 10^-5
2.14 x 2.05 x 10 ^4-5
2.14 x 2.05 x 10^-1
=4.387 x 10^-1
=4.39 x 10^-1
=0.439
Click here to see answer by Alan3354(69443)   |
Question 1154248: Use exponential function to solve: The number of deaths due to the pandemic in the united states is doubling every 3 days. This is called the doubling time. How long before there are 1 million deaths in this country given that there are 400 total right now.
Click here to see answer by josgarithmetic(39620) |
Question 1154250: Use Exponential function to solve: 75 million people died in World War 2 spread over 6 years. Right now in the World 13 000 people have died due to the pandemic. If the doubling time is 5 days (many people think it will decrease to 3 days) how long before the death toll will be greater than World War 2?
Click here to see answer by josmiceli(19441)  |
Question 1154466: Gabriella is going to invest $45,000 and leave it in an account for 9 years. Assuming the interest is compounded continuously, and earns 5.5%. How long would be required in order for Gabriella to end up with $74,000?
Click here to see answer by ikleyn(52802)  |
Question 1154500: There were 20 rabbits on an island. After six months the number of rabbits had increased to 100. If the number of rabbits increased exponentially, then how many rabbits will there be at the end of one year if the rate is .268?
Click here to see answer by ikleyn(52802) |
Question 1154249: Use Exponential function to solve: Every day 25 000 people die from hunger or hunger related diseases. This is the greatest killer of humanity at the moment. In this pandemic, about 2000 people are dying each day right now in the World. Suppose this is increasing by 12% every day (close to the correct number). When will the number of people dying each day exceed 25 000?
Click here to see answer by Theo(13342)  |
Question 1155003: 1.70 * 10e17 + 9.7 * 10e14
This is the way my professor solved it
(1.7 * 10e3 + 9.7) *10e14
(1.7x 1000 +9.7) * 10^14
(1700 + 9.7) * 10e14
17097 * 10e14
=1.71 * 10e17
I just don't know where the 10e3 came from at the very beginning. Can someone explain what he did here please.
Thank you!
Click here to see answer by ewatrrr(24785)  |
Question 1155003: 1.70 * 10e17 + 9.7 * 10e14
This is the way my professor solved it
(1.7 * 10e3 + 9.7) *10e14
(1.7x 1000 +9.7) * 10^14
(1700 + 9.7) * 10e14
17097 * 10e14
=1.71 * 10e17
I just don't know where the 10e3 came from at the very beginning. Can someone explain what he did here please.
Thank you!
Click here to see answer by MathTherapy(10552)  |
Question 1155412: Hello can someone please help me with this question:
Rewrite y=2(10)^{t/12} in the form y=a(1+r)^t or y=a(1-r)^t. Round the value of r to the nearest ten-thousandth. Then tell whether the model represents exponential growth or exponential decay.
I have tried, I know that it is exponential growth, but I really don't understand how to rewrite in this form.
Please help, Thanks.
Click here to see answer by ikleyn(52802) |
Question 1155414: Hello, can someone please help me with this problem:
Use the properties of exponents to rewrite y=4e^{-0.5t} in the form y=a(1+r)^t or y=a(1-r)^t . Round the value of r to the nearest thousandth. Then find the percent rate of change to the nearest tenth of percent.
I have tried but I really just don't understand how to do it.
Please help, Thanks.
Click here to see answer by ikleyn(52802) |
Question 1155415: Hello, can someone please help me with this problem:
Use the properties of exponents to rewrite y=4e^{-0.5t} in the form y=a(1+r)^t or y=a(1-r)^t . Round the value of r to the nearest thousandth. Then find the percent rate of change to the nearest tenth of percent.
I really need to know what the percent rate of change is.
I have tried but I really just don't understand how to do it.
Please help, Thanks.
Click here to see answer by MathLover1(20850)  |
Question 1155415: Hello, can someone please help me with this problem:
Use the properties of exponents to rewrite y=4e^{-0.5t} in the form y=a(1+r)^t or y=a(1-r)^t . Round the value of r to the nearest thousandth. Then find the percent rate of change to the nearest tenth of percent.
I really need to know what the percent rate of change is.
I have tried but I really just don't understand how to do it.
Please help, Thanks.
Click here to see answer by Edwin McCravy(20060)  |
Question 1155437: So I need help with these exponential function problems. I have solved for the most part using Logarithms, but I still do not understand how to graph them, I need to show full solutions so I thought if i graphed them The teacher would understand
A bicycle loses its value each month after it is purchased. It’s value as a function of time, in months, is modelled by V(m)=2200(0.98)^m. In which month after it is purchased does the bicycles worth fall below $1,500?
A 150 g sample of protactinium-233 has a half-life of 27 days. How long will it take for this sample to decay to 100 g?
Click here to see answer by greenestamps(13200)  |
Question 1155461: Hello, can someone please help me with this problem:
Rewrite y=5(1/4)^{t/6} in the form y=a(1+r)^t or y=a(1-r)^t. Round the value of r to the nearest ten-thousandth. Then tell whether the model represents exponential growth or exponential decay.
I know that it represents exponential decay but I don't understand how to rewrite in that form.
Someone, please help. Thanks
Click here to see answer by MathLover1(20850) |
Question 1155461: Hello, can someone please help me with this problem:
Rewrite y=5(1/4)^{t/6} in the form y=a(1+r)^t or y=a(1-r)^t. Round the value of r to the nearest ten-thousandth. Then tell whether the model represents exponential growth or exponential decay.
I know that it represents exponential decay but I don't understand how to rewrite in that form.
Someone, please help. Thanks
Click here to see answer by ikleyn(52802) |
Question 1155461: Hello, can someone please help me with this problem:
Rewrite y=5(1/4)^{t/6} in the form y=a(1+r)^t or y=a(1-r)^t. Round the value of r to the nearest ten-thousandth. Then tell whether the model represents exponential growth or exponential decay.
I know that it represents exponential decay but I don't understand how to rewrite in that form.
Someone, please help. Thanks
Click here to see answer by MathTherapy(10552) |
Question 1155852: A car is sold for $20,000. After one year, the value of the car is $13,000. Write an exponential function y to determine the value of the car after x years if the rate of decrease is the same each year.
y=20000(1-0.65)^x was my best guess, but that seems to be wrong.
Click here to see answer by ikleyn(52802) |
Question 1156049: You have 550-grams of an an unknown radioactive substance that has been determined to decay according to
D(t)=550e^-0.002334^(t)
where t is in years. How long before half of the initial amount has decayed?
It will take......years for half of the initial amount to decay. (Round to 1 decimal place)
Thank you.
Click here to see answer by josgarithmetic(39620) |
Question 1156574: NOTE: I phrased this question EXACTLY as it was given to me. A pot of boiling soup with an internal temperature of 100° Fahrenheit was taken off the stove to cool in a 75°F room. After fifteen minutes, the internal temperature of the soup was 93°F.
To the nearest minute, how long will it take the soup to cool to 80°F?
Click here to see answer by ikleyn(52802) |
Question 1157061: A piece of charcoal is found to contain 39% of the element B that it originally had.
(a) When did the tree from which the charcoal came die? Use 5800 years as the half-life of the element B.
(b) Using a graphing utility, graph the relation between the percentage of the element B remaining and time.
(c) Using INTERSECT, determine the time that elapses until half of the the element B remains.
(d) Verify the answer found in part (a).
Click here to see answer by ankor@dixie-net.com(22740)  |
Question 1157950: The Lualailua Hills Quadrangle of the East Maui (Haleakala) volcano on the island of
Maui in Hawaii is no longer active. To find out the date of the last eruption, scientists
conducted a chemical analysis of samples from the volcano area. The samples
contained approximately 62% of its original carbon-14. How long ago was the last
eruption of the volcano? Use 5730 years for the half-life of carbon-14.
Work must be shown!
Click here to see answer by Boreal(15235)  |
Question 1157950: The Lualailua Hills Quadrangle of the East Maui (Haleakala) volcano on the island of
Maui in Hawaii is no longer active. To find out the date of the last eruption, scientists
conducted a chemical analysis of samples from the volcano area. The samples
contained approximately 62% of its original carbon-14. How long ago was the last
eruption of the volcano? Use 5730 years for the half-life of carbon-14.
Work must be shown!
Click here to see answer by ikleyn(52802) |
Question 1157954: A radioactive isotope, selenium, used in the creation of medical images of the pancreas,
has a half-life of 119.77 days. If 100 milligrams are given to a patient, how many milligrams
are left after 20 days? Work must be shown!
Click here to see answer by ikleyn(52802) |
Question 1157955: Given an initial investment of $6,000 at 4.6% compounded continuously: Show all work!
a. Write the exponential growth function using the given information.
b. About how many years would it take for the investment to grow to $9,000?
c. About how long would it take the investment to double?
Click here to see answer by Boreal(15235) |
Question 1158515: The population of a particular city was 22 million in 1984; in 1994, it was 31 million. The exponential growth function A=22e^kt describes the population of this country t years after 1984. Use the fact that 10 years after 1984 the population increased by 9 million to find k to three decimal places.
Click here to see answer by Shin123(626)  |
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