Murky Well
THE CASE OF THE MURKY WELL


Deep Sheet-Rock Boulevard
Well Well, PU 10101
October 21, 1992

Calculus Student
Franklin & Marshall College
Lancaster, PA 17604

Dear Calculus Student:

In these times of great concern over the health of our planet, there are few people who do not know about the overwhelming problem of waste disposal. We entrepreneurs at Eco-Sludge are not immune to this concern; in fact, we are directly responsible for disposing of the waste by-products for the larger part of the state of PU. Unfortunately, our former board of managers, which has now been forcibly retired by the state's Environmental Agency, spent the greater part of its energies on improving cost-effectiveness to the grave detriment of safety and health. As a result, we are now faced with a expensive andwhat is worsedangerous cleaning project.

One of the first tasks facing us is estimating the total damage done. Your keen and piercing professor, Dr. "Death" Crannell, told me of your resounding success with the Jumping Gelatin Factory, and so I am being so bold as to ask you for help.

Our sludge is stored in large containers buried beneath the ground. These containers were manufactured with ease-of-construction in mind, and are really nothing more than parabolic holes in the ground, lined with concrete and covered with lids. (The problem is that the concrete cracks because of the changes in temperature due to our erratic climate. The sludge has been seeping out into the ground and making its way to the water supply. Needless to say, this is a horrendous state of affairs for our local fishers as well as for any inhabitant wishing to drink water from the faucet).

There are several measurements concerning the storage containers that we can make with ease. Obviously, we can determine the diameter and the radius of the vat's opening with a large tape measure. We have a plumbing rod that we can use to determine the depth of the container and also the depth of the sludge (this is done much the same way you check the oil in your car: by pulling the stick out and seeing how much of it is wet). According to specifications, each vat should be 40 feet across at the top and 40 feet deep. In reality, we have found that the measurements of the vats vary significantly, although the general parabolic shape does not. And, to no one's surprise, there is neither rhyme nor reason to the depth of sludge found in a particular vat.

What we can not easily determine is what we most need to know: the quantity (volume) of the sludge in any given vat. We are fairly certain that there is, however, a mathematical way of deriving this formula. We would be most grateful if you could help us with this, either in the standard (40'x40') case, oreven betterin the more general case.

Our report to the trustees must be mailed by November 6; could you please get the answer to us before that date? We await your reply with eagerness.

Yours sincerely,

N. Wiener


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