What are $\cos(\omega_k), -\sin(\omega_k)$ in Chebyshev filter design in matrix form?

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What are $\cos(\omega_k), -\sin(\omega_k)$ in Chebyshev filter design in matrix form?

The Chebyshev filter design problem "via SOCP" (https://en.wikipedia.org/wiki/Second-order_cone_programming) is formulated:

$$\min_x \| A^{(k)}h -b^{(k)}\|, k=1,...,m$$

where

$A^{(k)}=\begin{matrix} 1 & \cos \omega_k &...& \cos(n-1)\omega_k \\ 0 & -\sin \omega_k & ... & -\sin(n-1)\omega_k \end{matrix}$

$b^{(k)}=\begin{matrix} Re\space H_{des}(\omega_k) \\ Img \space H_{des}(\omega_k) \end{matrix}$

$h=\begin{matrix} h_0 \\ ... \\ h_{n-1} \\ \end{matrix}$