Question

The decay of 942 mg of an isotope is described by the function A(t)= 942e-0.012t, where t is time in years. Find the amount left after 71 years. Round your answer to the nearest mg.

Answer 1

That would be  942  e^(-0.012*71)  =  401.82 mg (answer)

Answer 2

$\bf A(t)=942e^{-0.012t}\qquad \boxed{\stackrel{\textit{after 71 years}}{t=71}}\qquad \qquad A(t)=942e^{-0.012(71)} \\\\\\ A(t)\approx 401.82042087707606813879$