# [SOLVED] Avoiding elliptic sine/cosine/etc

#### bubulescu

Hello,

I'd like to know if there is a possibility to avoid elliptic functions. My direct and practical case involves trying to find the poles and zeroes of a Cauer (elliptic) filter with the aid of a spice simulator. There are some mathematical formulae to work with but, unfortunately, they are limited; I am talking about LTspice.
So, I was wondering if there isn't a possibility to use something like Taylor series that would permit me to use some spice directives with more "gentle" formulae and calculate the poles and zeroes "on the spot"?

#### bubulescu

...nothing?

(This isn't a homework or anything like that. It's about an "universal filter" I'm trying to make.)

#### bubulescu

A simple yes or no will do, if all else, but I remember seing somewhere (and I keep looking for that, but luck isn't on my side) a series, something like:
u+2u^2+15*u^xxx+...
where u was function of k, from here on there were some approximations, etc (Pade?).