I'm trying to learn how to do equations of filters for synthesizer design. I am stuck on this:
https://s15.postimg.cc/eiuti9fbv/image.png
How did they get from the equation with the jw to the one without the j in it?
ie. How did they get rid of the "j"?
I need to be able to do this for other equations. I don't even know what the "j" is though I do understand the rest. If I can understand this I should be able to make gain equations for all the filter types I need.
Thanks.
That equation comes from: http://www.kves.uniza.sk/kvesnew/dokumenty/DREP/Filters/SecondOrderFilters.pdf
Edit: Solved. Thanks guys.
Since my comment apparently answered the question, I'll post it as an answer so the question can be closed:
What is often denoted by $j$ in electrical engineering and control system contexts is usually denoted by $\mathrm i$ in mathematics; see imaginary unit at Wikipedia.