# Thread: finding Vo and r from a straight line graph

1. ## finding Vo and r from a straight line graph

I have this question:

I've got my straight line by taking logs of V and plotting it in excel giving me this:

though I have no idea how to find r and Vo using it. I think the linear equation should be ln(V) = ln(Vo)+-r though might be wrong?

2. By taking logs, V = e^(-rt) can become f(t) = ln(V) = -rt. This is why the graph they gave you is labelled with "t" on the x-axis at "ln(V)" on the y-axis.

If ln(V) = -rt, then you must have V = e^(-rt). (Use what you've learned about logs to show this.)