1. The problem statement, all variables and given/known data I am working on the following problem: 3. The attempt at a solution I have the solutions, I just don't understand: I know that the pole should be the root of the denominator? but in all the examples I was given they used s and not jw, so what is the variable in the network function ? I am capable of deriving the network function, just a bit unsure of what the best method for finding the poles is. I also have an example in the book where they say: I've been trying to follow this logic. If we look at where ω<p1, I can see that they approximated both terms of the denominator by 1 and somehow got rid of the negative sign. For p1<ω<p2, it looks like they approximated the whole denominator by just jωC1R1... I don't understand how or why they did what they did in the solutions. Thanks.