I have the following fucntion: $$y=\frac{1}{C}(1-e^{-C(1-e^{-x})})$$
The term $C$ varies between $0<C<1$.
Some plots of the function are attached as images
Blue is for $C=1$, Yellow for $C=0.7$ and Green is for $C=0.5$
It can be seen that there is no abslute maxima, however the function saturates after a certain $x$.
Is there any way an approximate maxima expression involving $C$ can be deduced ?