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Find the derivative of \(\displaystyle f(x) = 8^{\cos{\left(\sin{\left(x \right)} \right)}}\).
Decomposing the function gives \(\displaystyle f(u) = 8^{u}\), \(\displaystyle u = \cos{\left(v \right)}\), and \(\displaystyle v = \sin{\left(x \right)}.\) Using the chain rule \(\displaystyle f'(x) = \frac{df}{du}\frac{du}{dv}\frac{dv}{dx}\). \(\displaystyle f'(x) = (8^{u} \ln{\left(8 \right)})(- \sin{\left(v \right)})(\cos{\left(x \right)}) = - 8^{u} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)}\). Substituting back in \(\displaystyle u\) and \(\displaystyle v\) gives \(\displaystyle f'(x) = - 8^{\cos{\left(v \right)}} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} = - 8^{\cos{\left(\sin{\left(x \right)} \right)}} \ln{\left(8 \right)} \sin{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)}\).
\begin{question}Find the derivative of $f(x) = 8^{\cos{\left(\sin{\left(x \right)} \right)}}$. \soln{9cm}{Decomposing the function gives $f(u) = 8^{u}$, $u = \cos{\left(v \right)}$, and $ v = \sin{\left(x \right)}.$ Using the chain rule $f'(x) = \frac{df}{du}\frac{du}{dv}\frac{dv}{dx}$. $f'(x) = (8^{u} \ln{\left(8 \right)})(- \sin{\left(v \right)})(\cos{\left(x \right)}) = - 8^{u} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)}$. Substituting back in $u$ and $v$ gives $f'(x) = - 8^{\cos{\left(v \right)}} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} = - 8^{\cos{\left(\sin{\left(x \right)} \right)}} \ln{\left(8 \right)} \sin{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)}$. } \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 f(x) = 8^{\cos{\left(\sin{\left(x \right)} \right)}} " src="/equation_images/%20%5Cdisplaystyle%20f%28x%29%20%3D%208%5E%7B%5Ccos%7B%5Cleft%28%5Csin%7B%5Cleft%28x%20%5Cright%29%7D%20%5Cright%29%7D%7D%20" alt="LaTeX: \displaystyle f(x) = 8^{\cos{\left(\sin{\left(x \right)} \right)}} " data-equation-content=" \displaystyle f(x) = 8^{\cos{\left(\sin{\left(x \right)} \right)}} " /> . </p> </p>
<p> <p>Decomposing the function gives <img class="equation_image" title=" \displaystyle f(u) = 8^{u} " src="/equation_images/%20%5Cdisplaystyle%20f%28u%29%20%3D%208%5E%7Bu%7D%20" alt="LaTeX: \displaystyle f(u) = 8^{u} " data-equation-content=" \displaystyle f(u) = 8^{u} " /> , <img class="equation_image" title=" \displaystyle u = \cos{\left(v \right)} " src="/equation_images/%20%5Cdisplaystyle%20u%20%3D%20%5Ccos%7B%5Cleft%28v%20%5Cright%29%7D%20" alt="LaTeX: \displaystyle u = \cos{\left(v \right)} " data-equation-content=" \displaystyle u = \cos{\left(v \right)} " /> , and <img class="equation_image" title=" \displaystyle v = \sin{\left(x \right)}. " src="/equation_images/%20%5Cdisplaystyle%20%20v%20%3D%20%5Csin%7B%5Cleft%28x%20%5Cright%29%7D.%20" alt="LaTeX: \displaystyle v = \sin{\left(x \right)}. " data-equation-content=" \displaystyle v = \sin{\left(x \right)}. " /> Using the chain rule <img class="equation_image" title=" \displaystyle f'(x) = \frac{df}{du}\frac{du}{dv}\frac{dv}{dx} " src="/equation_images/%20%5Cdisplaystyle%20f%27%28x%29%20%3D%20%5Cfrac%7Bdf%7D%7Bdu%7D%5Cfrac%7Bdu%7D%7Bdv%7D%5Cfrac%7Bdv%7D%7Bdx%7D%20" alt="LaTeX: \displaystyle f'(x) = \frac{df}{du}\frac{du}{dv}\frac{dv}{dx} " data-equation-content=" \displaystyle f'(x) = \frac{df}{du}\frac{du}{dv}\frac{dv}{dx} " /> . <img class="equation_image" title=" \displaystyle f'(x) = (8^{u} \ln{\left(8 \right)})(- \sin{\left(v \right)})(\cos{\left(x \right)}) = - 8^{u} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} " src="/equation_images/%20%5Cdisplaystyle%20f%27%28x%29%20%3D%20%288%5E%7Bu%7D%20%5Cln%7B%5Cleft%288%20%5Cright%29%7D%29%28-%20%5Csin%7B%5Cleft%28v%20%5Cright%29%7D%29%28%5Ccos%7B%5Cleft%28x%20%5Cright%29%7D%29%20%3D%20-%208%5E%7Bu%7D%20%5Cln%7B%5Cleft%288%20%5Cright%29%7D%20%5Csin%7B%5Cleft%28v%20%5Cright%29%7D%20%5Ccos%7B%5Cleft%28x%20%5Cright%29%7D%20" alt="LaTeX: \displaystyle f'(x) = (8^{u} \ln{\left(8 \right)})(- \sin{\left(v \right)})(\cos{\left(x \right)}) = - 8^{u} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} " data-equation-content=" \displaystyle f'(x) = (8^{u} \ln{\left(8 \right)})(- \sin{\left(v \right)})(\cos{\left(x \right)}) = - 8^{u} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} " /> . Substituting back in <img class="equation_image" title=" \displaystyle u " src="/equation_images/%20%5Cdisplaystyle%20u%20" alt="LaTeX: \displaystyle u " data-equation-content=" \displaystyle u " /> and <img class="equation_image" title=" \displaystyle v " src="/equation_images/%20%5Cdisplaystyle%20v%20" alt="LaTeX: \displaystyle v " data-equation-content=" \displaystyle v " /> gives <img class="equation_image" title=" \displaystyle f'(x) = - 8^{\cos{\left(v \right)}} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} = - 8^{\cos{\left(\sin{\left(x \right)} \right)}} \ln{\left(8 \right)} \sin{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)} " src="/equation_images/%20%5Cdisplaystyle%20f%27%28x%29%20%3D%20-%208%5E%7B%5Ccos%7B%5Cleft%28v%20%5Cright%29%7D%7D%20%5Cln%7B%5Cleft%288%20%5Cright%29%7D%20%5Csin%7B%5Cleft%28v%20%5Cright%29%7D%20%5Ccos%7B%5Cleft%28x%20%5Cright%29%7D%20%3D%20-%208%5E%7B%5Ccos%7B%5Cleft%28%5Csin%7B%5Cleft%28x%20%5Cright%29%7D%20%5Cright%29%7D%7D%20%5Cln%7B%5Cleft%288%20%5Cright%29%7D%20%5Csin%7B%5Cleft%28%5Csin%7B%5Cleft%28x%20%5Cright%29%7D%20%5Cright%29%7D%20%5Ccos%7B%5Cleft%28x%20%5Cright%29%7D%20" alt="LaTeX: \displaystyle f'(x) = - 8^{\cos{\left(v \right)}} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} = - 8^{\cos{\left(\sin{\left(x \right)} \right)}} \ln{\left(8 \right)} \sin{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)} " data-equation-content=" \displaystyle f'(x) = - 8^{\cos{\left(v \right)}} \ln{\left(8 \right)} \sin{\left(v \right)} \cos{\left(x \right)} = - 8^{\cos{\left(\sin{\left(x \right)} \right)}} \ln{\left(8 \right)} \sin{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)} " /> . </p> </p>