Decay-1
**Exponential Decay -- Example**

**Problem: **
A radioactive isotope of iodine decays exponentially.
There is 50 mg of the element initially, 35 mg after 4 days.

(a) Find a formula of the form

that models the process of decay.
(b) Find the half-life,
, of the isotope.

* Precalculus Tutorials, B. Kaskosz and L. Pakula, 2002.
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