I'm stuck on a really simple problem because I haven't done matlab in a while. I have transfer functions for nth order lowpass Butterworth Filters: H(jw) = 1/(s + w_c)^n I want to plot the 1st to 5th order filters. How do I input H(jw) into matlab? The tf(num, den) is not efficient in that case because I would have to expand out the denominator. I already know the zeros and poles of my transfer function so would there be an easier way to implement H(jw)? Thanks.