Hi, could someone please help me with this error I keep receiving?

My code is:

syms k w0;
% Let filter be 1st order
k=1;
% Cutoff frequency - passes frequencies above 0.1 
w0=0.1;
[n,d]=cheby1(k,w0,'high','s')

I receive the error:
??? Error using ==> cheby1 at 41
Wn must be a one or two element vector.

Therefore, I changed w0 to a two element vector:

syms k w0;
% Let filter be 1st order
k=1;
% Cutoff frequency - passes frequencies above 0.1 
w0=[0.1 0.9];
[n,d]=cheby1(k,w0,'high','s')

Yet, I still receive the exact same error. Does anyone know what the problem might be?

 

Check the order of input arguments of cheby1(). You forgot to specify the passband ripple.