Linearize poisson-boltzmann equation

[barcafan]

Homework Statement

Need to linearize the poisson-boltzmann equation to be used later in the problem. I simply have never linearized an equation and searching google didn't really help me understand.

Homework Equations

http://img215.imageshack.us/img215/2149/eqnq.jpg

The Attempt at a Solution

Just need an idea of how to go about this in order to complete the question.

 

[barcafan]

To "linearize" means take an expansion to its linear term. I am still stuck on this. Any help would be great.