# Homework Help: Solving equation with log

1. Feb 5, 2012

### likephysics

1. The problem statement, all variables and given/known data
Can you solve an unknown equal to some constant+log of unknown.
All the other variables are known, except Ic1.
How to you solve this?

2. Relevant equations

3. The attempt at a solution
I have no idea.

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2. Feb 5, 2012

### HallsofIvy

If you have $I_{C1}$ both "inside" and "outside" the logarithm, the equation cannot be solved in terms of "elementary" functions. It very likely can be solved, though still non-trivial, in terms of the "Lambert W function" which is defined as the inverse function to $f(x)= xe^x$.