1. The problem statement, all variables and given/known data Transpose for t, x=12(1-e^(-t/RC)) I can't get it out of my head but, the soltuion I have come up with doesn't seem right. Solution is, t=-RC ln(1-x/12) Thanks in advance, Realted, but not as important as the sanity check. For my own mind, could someone explain to me if this is possible and should/could be carried out. If during my transposing I came up with: e^(-t/RC)= (12-x)/12 Is it possible to invert both sides so that the follwoing is shown e^(t/RC)=12/(12-x) Again, thanks in advance.