# Please Help Us Prepare For The Semester Exam!!!! Part 2

• Jan 15th 2008, 12:29 PM
rlarach
Please Help Us Prepare For The Semester Exam!!!! Part 2
This is the part 2 of our study guide.

Solve the equation.

1. 2.7^x = 4
2. ln x - ln(3x - 5) = 2
3. The number of redwood saplings in a forested study area has been determined to be approximated by the function:
N(t) = 720/1 + 19e^(0.15t)

when t is the time (in years) after the study was begun.

a. What was the initial number of saplings?
b. When will the number of saplings be 370?
c. What is the carrying capacity, the maximum number of saplings possible in the study area?

THANK YOU VERY MUCH WE REALLY APPRECIATE YOUR HELP!!:)

4. The half-life of lead-209 is 3.3 hours. The initial amount S grams.

a. Express the amoundt of substance S remaining as a function of time t.
b. How mmuch of the substance is left after 3.3 hourse? after 33 hours?
c. Determine S if there is 5 g left after 22 hours.
• Jan 15th 2008, 12:44 PM
colby2152
Please do not post many problems within one post, and expect people to answer every problem. You obviously need assistance with logs. Try checking this out first: Properties of Logarithms

Review your problems, and then ask why and how, not what.
• Jan 15th 2008, 01:21 PM
mr fantastic
Quote:

Originally Posted by rlarach
This is the part 2 of our study guide.

Solve the equation.

1. 2.7^x = 4
2. ln x - ln(3x - 5) = 2
3. The number of redwood saplings in a forested study area has been determined to be approximated by the function:
N(t) = 720/1 + 19e^(0.15t)

when t is the time (in years) after the study was begun.

a. What was the initial number of saplings?
b. When will the number of saplings be 370?
c. What is the carrying capacity, the maximum number of saplings possible in the study area?

THANK YOU VERY MUCH WE REALLY APPRECIATE YOUR HELP!!:)

4. The half-life of lead-209 is 3.3 hours. The initial amount S grams.

a. Express the amoundt of substance S remaining as a function of time t.
b. How mmuch of the substance is left after 3.3 hourse? after 33 hours?
c. Determine S if there is 5 g left after 22 hours.

From what I can see, some (if not most or all) of these question have been re-posted as individual questions. PLEASE DON'T DO THAT! (Do you understand why??)

What I will do (and probably others) is ignore the questions here and perhaps take a look at the individual re-posted questions.
• Jan 15th 2008, 05:11 PM
topsquark
I'm beginning to wonder how many questions on this review these students were able to do on their own...

-Dan
• Jan 15th 2008, 05:34 PM
Krizalid
Quote:

Originally Posted by rlarach
THANK YOU VERY MUCH WE REALLY APPRECIATE YOUR HELP!!:)

Of course you do appreciate our help, but this doesn't make sense.

Quote:

Originally Posted by topsquark
I'm beginning to wonder how many questions on this review these students were able to do on their own...

If they at least show us a little of work, may be one can get more energy to solve problems.

I think they don't understand anything makin' them the entire homework.