Find the half-life of each radioactive substance, where t is measured in years. See Example 2.

Krypton-85: A(t) = A₀e^-0.0644t.

Data from Example 2.

Carbon-14 is a radioactive form of carbon that is found in all living plants and animals. After a plant or animal dies, the carbon-14 disintegrates. Scientists determine the age of the remains by comparing its carbon-14 with the amount found in living plants and animals. The amount of carbon-14 present after t years is given by the exponential equation

A(t0 = A₀ e^kt,

with k = - [(ln 2)/5600].