Signals and Systems: Designing a filter using invfreqs?

Given a time-domain sinusoidal function like this: x(t) = sin(at)cos(bt) + sin(ct)cost(dt)

How do I filter out one term using invfreqs??

from looking up what invfreqs is I find that it can give me h(t) if I provide H(s). So do I have to design an H(s) that works as a filter? I have no idea how to design a filter.

Here is the plan:

Find X(s) with each of the two terms: x(t) = x1(t) + x2(t) X(s) = X1(s) + X2(s)

Then plot X1(s) and X2(s) to find range of frequency

Then copy "butterworth" filter by putting in the cutoff frequency.

Hopefully my professor will actually teach us how to do this in our last lecture.

Any help would be greatly appreciated.