Tentukan turunan dari \(y = (2x + 1)^3 (4 - 5x)^4\)
\begin{equation*} \begin{split} u & = (2x + 1)^3 \\\\ u' & = 3 \:.\: 2 \:.\: (2x + 1)^2 \\\\ u' & = 6 \: (2x + 1)^2 \end{split} \end{equation*}
\begin{equation*} \begin{split} v & = (4 - 5x)^4 \\\\ v' & = 4 \:.\: -5 \:.\: (4 - 5x)^3 \\\\ v' & = - 20 \: (4 - 5x)^3 \end{split} \end{equation*}
\begin{equation*}
\begin{split}
y' & = u' \:.\: v + u \:.\: v' \\\\
y' & = 6 \: (2x + 1)^2 \:.\: (4 - 5x)^4 + (2x + 1)^3 \:.\: 4 \:.\: -5 \: (4 - 5x)^3 \\\\
y' & = 6 \: (2x + 1)^2 \: (4 - 5x)^4 - 20 \: (4 - 5x)^3 \: (2x + 1)^3 \\\\
y' & = (2x + 1)^2 \: (4 - 5x)^3 \: [6(4 - 5x) - 20(2x + 1) ] \\\\
y' & = (2x + 1)^2 \: (4 - 5x)^3 \: [24 - 30x - 40x - 20] \\\\
y' & = (2x + 1)^2 \: (4 - 5x)^3 \: (-70x + 4)
\end{split}
\end{equation*}