Posted by Anonymous on .
1/2 life of R 226 if A(t)=600e^0.00043t
i got stuck
A(t)=A(t)=600e
A(t)=600/2=300
300=A(t)=600e

math 
Steve,
300 = 600e^.00043t
1/2 = e^.00043t
ln2 = .00043t
t = 1612
so, after 1612 years, half is gone. That's the halflife.
Check: web search reveals a halflife of 1600 years or so.