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$9.[-/3$ Points$]$

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SCALCET$94\mathrm{.}3\mathrm{.}02$

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Consider the following. $($If an answer does not exist, enter DNE.$)$

$f(x)=\frac{e^x}{e^{x}5}$

Find the interval$($s$)$ on which $f$ is concave up$.($Enter your answer using

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Find the interval$($s$)$ on which $f$ is concave down. $($Enter your answer usi

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Find the inflection point of $f.$

$(x,y)=()$