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\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
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\begin{document}
\begin{equation*}
  y(t) = G(i\omega) e^{i\omega t} 
    = M e^{i(\omega t + \phi)} = M \cos(\omega t + \phi) + i M
  \sin(\omega t + \phi).
\end{equation*}
\end{document}