Hello!
I am pretty new to Mathematica. I actually started to learn it for solving a specific problem: finding the inverse of the following function:
$f(x) = \sum_{i=1}^n \frac{b_i}{1 + e^{c_i(x-a_i)}}$ for a specific $n \in \mathbb{N}$
The $a_i, b_i, c_i \in \mathbb{R}^+$ are constants. I can solve the trivial case of $n = 1$ by hand and it agrees with the result provided by WolframAlpha and Mathematica. The case of $n = 2$, written explicitly (without the sum notation), can be solved by WolframAlpha, but on Mathematica I do not get an explicit formulation (see below).
Could you please help me to get an explicit solution for the case $n = 2$ and higher?
Do I write the query correctly?
