Suppose that a radioactive isotope has a
half-life of 5 days. If there are 200 milligrams at t = 0
and if the amount A(t) remaining after t days is given by A(t) =
200 e - .139 t , then
i) find amount remaining after 8 days
ii) sketch the graph of the function A for 0 < t < 20
iii) using the graph, approximate the number of days elapsed
until only 75 milligrams remain.
| A(8) = 200 e (-.139)(8) = 66 (rounded value) |
Find the amount remaining after 8 days. Round the answer to the nearest whole number. |
| Show work. | Sketch the graph of A for 0 < t < 20. |
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