\left[ \begin{gathered}
 \varphi \left( t \right) = 9\cos ^2 t - 8\sin ^3 t \hfill \\
 \varphi '\left( t \right) = 2\left( { - 3\cos t\sin t\left( {3 + 4\sin t} \right)} \right) \hfill \\ 
\end{gathered} \right]