Solve for L: Unknown Exponential Function & Plain Side

[lookingforhlp]

I am doing a heat transfer problem and I need to solve for the length of something. I have reduced the equation to this:

[C3/C1*L] = e^(-C2*L)

Find L
Where: C1, C2, & C3 are constants

Please help I am in a real bind!

 

[lurflurf]

You need a function such as the Lambert W function. Otherwise solve numerically.

C2L e^(C2L)=C1C2/C3

is the standard form for the Lambert W function