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Brioz
07-21-2011, 10:04 AM
Having trouble with these. Maybe one of you guys can help me out.

1. If \$1,000 is invested for x years at 8%, compounded quarterly, the future value is given by A= 1000(1.02)^4x. Then the future value after 10 years is what?

2. If \$1,000 is invested for x years at %10, compounded continuously, the future value is given by A= 1000e^0.01x. Then the future value after 7 years is what?

3.The Richter scale of earthquakes is given by the formula R= log(I/Io) (You can assume Io is 1). The San Francisco earthquake of 1906 measured 8.25 on the Richter scale and the San Francisco earthquake of 1989 measured 7.1. Then, comparing to 1989 quake, 1906 quake is how many times more severe?

The concentration of a drug is an at any time t (in seconds) is given by x(t)= 0.08(1-e^-0.02t) where x(t) is measured in grams/cubic centimeter (g/cm^3)

4. How long will it take for the concentration of the drug in the organ to reach 0.02 g/cm^3?
5. How long will it take for the concentration of the drug in the organ to reach 0.02 g/cm^3?

When one person in 10,000 is infected by a disease, the spread of the disease is given by y= 10,000/ 1 + 9999e^-0.99t where y is the total number infected at a time t (in days.)

6.After 3 days, the total number infected is ? (round to integer)
7. After how many days will 3,000 be infected?

Thanks for all help :)

Subhotosh Khan
07-21-2011, 12:15 PM
Having trouble with these. Maybe one of you guys can help me out.

1. If \$1,000 is invested for x years at 8%, compounded quarterly, the future value is given by A= 1000(1.02)^4x. Then the future value after 10 years is what?

This one is simple substitution-evaluation problem - showing you an example and gives you the equation. Where are you stuck?

2. If \$1,000 is invested for x years at %10, compounded continuously, the future value is given by A= 1000e^0.01x. Then the future value after 7 years is what?

3.The Richter scale of earthquakes is given by the formula R= log(I/Io) (You can assume Io is 1). The San Francisco earthquake of 1906 measured 8.25 on the Richter scale and the San Francisco earthquake of 1989 measured 7.1. Then, comparing to 1989 quake, 1906 quake is how many times more severe?

The concentration of a drug is an at any time t (in seconds) is given by x(t)= 0.08(1-e^-0.02t) where x(t) is measured in grams/cubic centimeter (g/cm^3)

4. How long will it take for the concentration of the drug in the organ to reach 0.02 g/cm^3?
5. How long will it take for the concentration of the drug in the organ to reach 0.02 g/cm^3?

When one person in 10,000 is infected by a disease, the spread of the disease is given by y= 10,000/ 1 + 9999e^-0.99t where y is the total number infected at a time t (in days.)

6.After 3 days, the total number infected is ? (round to integer)
7. After how many days will 3,000 be infected?

Thanks for all help :)

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