Elimination rate constant k in terms of other variables

[Claud]

Trying to solve this for k: solve(Ct=(C0*exp(-1*k*t))/(1-exp(-1*k*t))),k

This is what it returns: -C0*exp(-k*t)+Ct*(-exp(-k*t)+1)

As you can see, this isn't what I'm looking for. Can anyone help?

[arsastronautica]

Try

solve(Ct=(C0*exp(-1*k*t))/(1-exp(-1*k*t)),k)

with the parenthesis in the correct position.