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Radioactive decay. The continuous compound rate of decay of carbon-14 per year is r = −0.000 123 8. How long will it take a certain amount of carbon-14 to decay to half the original amount? (Use the radioactive decay model in Problem 43.)
43. Radioactive decay. A mathematical model for the decay of radioactive substances is given by
where
If the continuous compound rate of decay of radium per year is r = −0.000 433 2, how long will it take a certain amount of radium to decay to half the original amount? (This period is the half-life of the substance.)
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