Matlab Nyquist Sampling Problem

How can I make my nyquist function more smooth?

This is my code

s=tf('s');

k1=3/(2*s*s+5*s+1);

nyquist(k1)

Answer 1

[Paul]

According to

doc nyquist

you can do

nyquist(k1,w)

where w is a frequency vector of your choosing.