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Find the derivative of
Taking the natural logarithm of both sides of the equation and expanding the right hand side gives:
\begin{question}Find the derivative of $y = \frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}}$ \soln{9cm}{Taking the natural logarithm of both sides of the equation and expanding the right hand side gives: \begin{equation*}\ln(y) = \ln{\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right)} \end{equation*} Expanding the right hand side using the product and quotient properties of logarithms gives: \begin{equation*}\ln(y) = x + 4 \ln{\left(6 x - 7 \right)} + 8 \ln{\left(7 x + 3 \right)}- 4 \ln{\left(x - 4 \right)} - \frac{5 \ln{\left(8 x + 4 \right)}}{2} \end{equation*} Taking the derivative on both sides of the equation yields: \begin{equation*}\frac{y'}{y} = 1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4} \end{equation*} Solving for $y'$ and substituting out y using the original equation gives \begin{equation*}y' = \left(1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4}\right)\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right) \end{equation*} } \end{question}
\documentclass{article} \usepackage{tikz} \usepackage{amsmath} \usepackage[margin=2cm]{geometry} \usepackage{tcolorbox} \newcounter{ExamNumber} \newcounter{questioncount} \stepcounter{questioncount} \newenvironment{question}{{\noindent\bfseries Question \arabic{questioncount}.}}{\stepcounter{questioncount}} \renewcommand{\labelenumi}{{\bfseries (\alph{enumi})}} \newif\ifShowSolution \newcommand{\soln}[2]{% \ifShowSolution% \noindent\begin{tcolorbox}[colframe=blue,title=Solution]#2\end{tcolorbox}\else% \vspace{#1}% \fi% }% \newcommand{\hideifShowSolution}[1]{% \ifShowSolution% % \else% #1% \fi% }% \everymath{\displaystyle} \ShowSolutiontrue \begin{document}\begin{question}(10pts) The question goes here! \soln{9cm}{The solution goes here.} \end{question}\end{document}
<p> <p>Find the derivative of <img class="equation_image" title=" \displaystyle y = \frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} " src="/equation_images/%20%5Cdisplaystyle%20y%20%3D%20%5Cfrac%7B%5Cleft%286%20x%20-%207%5Cright%29%5E%7B4%7D%20%5Cleft%287%20x%20%2B%203%5Cright%29%5E%7B8%7D%20e%5E%7Bx%7D%7D%7B%5Cleft%28x%20-%204%5Cright%29%5E%7B4%7D%20%5Csqrt%7B%5Cleft%288%20x%20%2B%204%5Cright%29%5E%7B5%7D%7D%7D%20" alt="LaTeX: \displaystyle y = \frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} " data-equation-content=" \displaystyle y = \frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} " /> </p> </p>
<p> <p>Taking the natural logarithm of both sides of the equation and expanding the right hand side gives:
<img class="equation_image" title=" \ln(y) = \ln{\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right)} " src="/equation_images/%20%5Cln%28y%29%20%3D%20%5Cln%7B%5Cleft%28%5Cfrac%7B%5Cleft%286%20x%20-%207%5Cright%29%5E%7B4%7D%20%5Cleft%287%20x%20%2B%203%5Cright%29%5E%7B8%7D%20e%5E%7Bx%7D%7D%7B%5Cleft%28x%20-%204%5Cright%29%5E%7B4%7D%20%5Csqrt%7B%5Cleft%288%20x%20%2B%204%5Cright%29%5E%7B5%7D%7D%7D%20%5Cright%29%7D%20%20%20" alt="LaTeX: \ln(y) = \ln{\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right)} " data-equation-content=" \ln(y) = \ln{\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right)} " />
Expanding the right hand side using the product and quotient properties of logarithms gives:
<img class="equation_image" title=" \ln(y) = x + 4 \ln{\left(6 x - 7 \right)} + 8 \ln{\left(7 x + 3 \right)}- 4 \ln{\left(x - 4 \right)} - \frac{5 \ln{\left(8 x + 4 \right)}}{2} " src="/equation_images/%20%5Cln%28y%29%20%3D%20x%20%2B%204%20%5Cln%7B%5Cleft%286%20x%20-%207%20%5Cright%29%7D%20%2B%208%20%5Cln%7B%5Cleft%287%20x%20%2B%203%20%5Cright%29%7D-%204%20%5Cln%7B%5Cleft%28x%20-%204%20%5Cright%29%7D%20-%20%5Cfrac%7B5%20%5Cln%7B%5Cleft%288%20x%20%2B%204%20%5Cright%29%7D%7D%7B2%7D%20%20%20" alt="LaTeX: \ln(y) = x + 4 \ln{\left(6 x - 7 \right)} + 8 \ln{\left(7 x + 3 \right)}- 4 \ln{\left(x - 4 \right)} - \frac{5 \ln{\left(8 x + 4 \right)}}{2} " data-equation-content=" \ln(y) = x + 4 \ln{\left(6 x - 7 \right)} + 8 \ln{\left(7 x + 3 \right)}- 4 \ln{\left(x - 4 \right)} - \frac{5 \ln{\left(8 x + 4 \right)}}{2} " />
Taking the derivative on both sides of the equation yields:
<img class="equation_image" title=" \frac{y'}{y} = 1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4} " src="/equation_images/%20%5Cfrac%7By%27%7D%7By%7D%20%3D%201%20-%20%5Cfrac%7B20%7D%7B8%20x%20%2B%204%7D%20%2B%20%5Cfrac%7B56%7D%7B7%20x%20%2B%203%7D%20%2B%20%5Cfrac%7B24%7D%7B6%20x%20-%207%7D%20-%20%5Cfrac%7B4%7D%7Bx%20-%204%7D%20%20%20" alt="LaTeX: \frac{y'}{y} = 1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4} " data-equation-content=" \frac{y'}{y} = 1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4} " />
Solving for <img class="equation_image" title=" \displaystyle y' " src="/equation_images/%20%5Cdisplaystyle%20y%27%20" alt="LaTeX: \displaystyle y' " data-equation-content=" \displaystyle y' " /> and substituting out y using the original equation gives
<img class="equation_image" title=" y' = \left(1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4}\right)\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right) " src="/equation_images/%20y%27%20%3D%20%5Cleft%281%20-%20%5Cfrac%7B20%7D%7B8%20x%20%2B%204%7D%20%2B%20%5Cfrac%7B56%7D%7B7%20x%20%2B%203%7D%20%2B%20%5Cfrac%7B24%7D%7B6%20x%20-%207%7D%20-%20%5Cfrac%7B4%7D%7Bx%20-%204%7D%5Cright%29%5Cleft%28%5Cfrac%7B%5Cleft%286%20x%20-%207%5Cright%29%5E%7B4%7D%20%5Cleft%287%20x%20%2B%203%5Cright%29%5E%7B8%7D%20e%5E%7Bx%7D%7D%7B%5Cleft%28x%20-%204%5Cright%29%5E%7B4%7D%20%5Csqrt%7B%5Cleft%288%20x%20%2B%204%5Cright%29%5E%7B5%7D%7D%7D%20%5Cright%29%20%20%20" alt="LaTeX: y' = \left(1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4}\right)\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right) " data-equation-content=" y' = \left(1 - \frac{20}{8 x + 4} + \frac{56}{7 x + 3} + \frac{24}{6 x - 7} - \frac{4}{x - 4}\right)\left(\frac{\left(6 x - 7\right)^{4} \left(7 x + 3\right)^{8} e^{x}}{\left(x - 4\right)^{4} \sqrt{\left(8 x + 4\right)^{5}}} \right) " />
</p> </p>