Question

Doctors use radioactive iodine as a tracer in diagnosing certain thyroid gland disorders. This type of iodine decays in such a way that the mass remaining after t days is given by the function

m(t) = 2e−0.083t
where m(t) is measured in grams.
(a) Find the mass at time t = 0.
grams

(b) How much of the mass remains after 2 days? (Round your answer to three decimal places.)
grams

Answer 1

a. The mass at time t = 0 is 2 grams

b. After 2 days, 1.694 grams of the mass remains.

How to find the mass

(a) To find the mass at time (t = 0), substitute (t = 0) into the given function:

m(t) =
`2e^(-0.083t)`

pugging in t = 0

m = 2 * 1

m = 2 grams

(b) To find how much of the mass remains after 2 days, substitute (t = 2)

m =
`2e^(-0.083(2))`

m = 1.6941

After 2 days, about 1.694 grams of the mass remains.