Hi,

I would like to find the solution for t in;

a*t=1/(1+c*exp(-b*t))

where a, b and c are all positive and less than 1. Left hand side of the function is cumulative logistics curve. I know it is not invertible, I am assuming the solution would include LambertW function. Is there a way to find t in closed form (using LambertW or any other functions)?

Thanks,

rutabaga