Thread: half life

I have the function A(t) with its differential equation of dA/dt= -kA
and the solution as a function: A(t)= Ao e^-kt.

I need to find the values of Ao and k in the equation A(t) before i
can continue with the rest of the question.

I think i've found the values for k but not 100% but have no idea
about Ao

i found k= 1.2092x 10^-4

Originally Posted by bungy189

I have the function A(t) with its differential equation of dA/dt= -kA
and the solution as a function: A(t)= Ao e^-kt.

I need to find the values of Ao and k in the equation A(t) before i
can continue with the rest of the question.

I think i've found the values for k but not 100% but have no idea
about Ao

i found k= 1.2092x 10^-4

We can't help you until you tell us what your boundary conditions are.

-Dan

The question is to do with the amount of C-14 as a percentage. The half life of C14 is 5730....

Your k value is correct (well, I get $\displaystyle k = ln(2)/5730 \approx 1.2097 \times 10^{-4}$.)

The physical meaning of $\displaystyle A_0$ is the amount of C-14 present at time 0. You can't determine that from the information you have given us.

-Dan