$\begin{array}{ll}\\ 1.&\textrm{Diketahui}\: \: {f}\, '(2)=\underset{x\rightarrow 2}{\textrm{Lim}}\: \: \displaystyle \frac{x^{3}-8}{x-2},\\ & \textrm{maka fungsi}\: \: f(x)=....\\ &\begin{array}{lll}\\ \textrm{a}.\quad 12&&\textrm{d}.\quad \color{red}x^{3}\\ \textrm{b}.\quad 2\quad&\textrm{c}.\quad x\quad&\textrm{e}.\quad x-8 \end{array}\\\\ &\textbf{Jawab}:\\ &\begin{aligned} &\textrm{Turunan fungsi f di}\: \: x=c\: \: \textrm{adalah}\\ &f\, '(c)=\underset{x\rightarrow c}{\textrm{Lim}}\: \: \displaystyle \frac{f(x)-f(c)}{x-c},\: \: \textrm{maka}\\ &\textrm{turunan fungsi f di}\: \: x=2\: \: \textrm{adalah}\\ &f\, '(2)=\underset{x\rightarrow 2}{\textrm{Lim}}\: \: \displaystyle \frac{x^{3}-8}{x-2}\\ &\textrm{sehingga akan didapa}\textrm{tkan fungsi}\: \: f\: \: \textrm{nya }\\ &\textrm{yaitu}\: \: f(x)=\color{red}x^{3} \end{aligned} \end{array}$.
$\begin{array}{ll}\\ 2.&\textrm{Jika}\: \: a\neq 0\, ,\: \textrm{maka nilai dari}\\&\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{\displaystyle \sqrt[3]{x}-\displaystyle \sqrt[3]{a}}{x-a}=....\\ &\begin{array}{lll}\\ \textrm{a}.\quad 3a\displaystyle \sqrt[3]{a}&&\textrm{d}.\quad \displaystyle \frac{1}{2a}\sqrt[3]{a} \\ \textrm{b}.\quad 2a\displaystyle \sqrt[3]{a} \quad&\textrm{c}.\quad 0\quad&\textrm{e}.\quad \color{red}\displaystyle \frac{1}{3a}\sqrt[3]{a} \end{array}\\\\ &\textbf{Jawab}:\\ &\color{blue}\textrm{Alternatif 1}\\ &\begin{aligned}{f}\, '(a)&=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{\displaystyle \sqrt[3]{x}-\displaystyle \sqrt[3]{a}}{x-a}\\ &=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{\displaystyle \sqrt[3]{x}-\displaystyle \sqrt[3]{a}}{\left ( \sqrt[3]{x}-\sqrt[3]{a} \right )\left ( \sqrt[3]{x^{2}}+\sqrt[3]{xa}+\sqrt[3]{a^{2}} \right )}\\ &=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{1}{\left ( \sqrt[3]{x^{2}}+\sqrt[3]{xa}+\sqrt[3]{a^{2}} \right )}\\ &=\displaystyle \frac{1}{\left ( \sqrt[3]{a^{2}}+\sqrt[3]{a.a}+\sqrt[3]{a^{2}} \right )}\\ &=\displaystyle \frac{1}{3\sqrt[3]{a^{2}}}\\ &=\displaystyle \frac{1}{3\sqrt[3]{a^{2}}}\times \displaystyle \frac{\sqrt[3]{a}}{\sqrt[3]{a}}\\ &=\displaystyle \frac{1}{3a}\sqrt[3]{a} \end{aligned}\\ &\color{blue}\textrm{Alternatif 2 (dengan aturan L'Hopital)}\\&\begin{aligned}\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{\displaystyle \sqrt[3]{x}-\displaystyle \sqrt[3]{a}}{x-a}&=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{f(x)}{g(x)}\\ &=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{{f}\, '(x) }{{g}\, '(x) }\\ \underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{\displaystyle \sqrt[3]{x}-\displaystyle \sqrt[3]{a}}{x-a}&=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{x^{^{\frac{1}{3}}}-a^{^{\frac{1}{3}}} }{x-a}\\ &=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{\displaystyle \frac{1}{3}x^{^{\frac{1}{3}-1}}\: -0}{1-0}\\ &=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{\displaystyle \frac{1}{3}x^{^{-\frac{2}{3}}}}{1}\\ &=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{1}{3\sqrt[3]{x^{2}}}\times \frac{\sqrt[3]{x}}{\sqrt[3]{x}}\\ &=\underset{x\rightarrow a}{\textrm{Lim}}\: \: \displaystyle \frac{1}{3x}\sqrt[3]{x}\\ &=\displaystyle \frac{1}{3a}\sqrt[3]{a} \end{aligned} \end{array}$ .
$\begin{array}{ll}\\ 3.&\textrm{Jika}\: \: f(x)=\displaystyle \frac{1}{\sqrt{x}}\: \: \textrm{maka nilai dari}\\ & -2{f}\, '(x)=....\\ &\begin{array}{lll}\\ \textrm{a}.\quad \displaystyle \frac{1}{x\sqrt{x}} &&\textrm{d}.\quad \displaystyle \color{red}-\frac{1}{2x\sqrt{x}} \\ \textrm{b}.\quad \displaystyle x\sqrt{x} \quad&\textrm{c}.\quad \displaystyle -\frac{1}{2\sqrt{x}} \quad&\textrm{e}.\quad \displaystyle -2x\sqrt{x} \end{array}\\\\&\textbf{Jawab}:\\&\begin{aligned}\textrm{Dike}&\textrm{tahui}\\ f(x)&=\displaystyle \frac{1}{\sqrt{x}}=\displaystyle \frac{1}{x^{^{\frac{1}{2}}}}=x^{^{-\frac{1}{2}}} \end{aligned}\\ &\begin{array}{|c|c|}\hline y=ax^{n}\rightarrow {y}\, '=nax^{n-1}&\begin{aligned}&\\ y&=\displaystyle \frac{U}{V}\rightarrow {y}\, '=\displaystyle \frac{{U}'.V-U.{V}'}{V^{2}}\\ & \end{aligned}\\\hline \begin{aligned} {f}\, '(x)&=-\displaystyle \frac{1}{2}x^{^{-\frac{1}{2}-1}}\\ &=-\displaystyle \frac{1}{2}x^{^{-\frac{3}{2}}}\\ &=-\displaystyle \frac{1}{2x^{^{\frac{3}{2}}}}\\ &=-\displaystyle \frac{1}{2x^{1}.x^{^{\frac{1}{2}}}}\\ &=-\displaystyle \frac{1}{2x\sqrt{x}} \end{aligned}&\begin{aligned} {f}\, '(x)&=\displaystyle \frac{0.\sqrt{x}-1.\frac{1}{2}x^{^{\frac{1}{2}-1}}}{\left ( \sqrt{x}\right )^{2}}\\ &=\displaystyle \frac{-\displaystyle \frac{1}{2}x^{^{-\frac{1}{2}}}}{x}\\ &=-\displaystyle \frac{1}{2xx^{^{\frac{1}{2}}}}\\ &=-\displaystyle \frac{1}{2x\sqrt{x}} \end{aligned}\\\hline \end{array} \end{array}$.
$\begin{array}{ll}\\ 4.&\textrm{Turunan pertama dari}\: \: y=\displaystyle \sqrt[n]{x}\: \: \textrm{adalah}.... \\ &\begin{array}{lll}\\ \textrm{a}.\quad \displaystyle \frac{1}{n}x^{^{\frac{1}{n}}}&&\textrm{d}.\quad (n-1)\sqrt[n-1]{x}\\ \textrm{b}.\quad \displaystyle \color{red}\frac{1}{n}x^{^{\frac{1-n}{n}}}\quad &\textrm{c}.\quad \displaystyle \frac{1}{n-1}x^{^{n-1}}\quad &\textrm{e}.\quad \sqrt[n-1]{x} \end{array}\\\\ &\textbf{Jawab}:\\ &\begin{aligned}y&=\sqrt[n]{x}=\displaystyle x^{^{\frac{1}{n}}},\: \: \textrm{maka}\\ {y}\, '&=\displaystyle \frac{1}{n}x^{^{\frac{1}{n}-1}}=\displaystyle \frac{1}{n}x^{^{\frac{1-n}{n}}} \end{aligned} \end{array}$.
$\begin{array}{ll}\\ 5.&\textrm{Turunan ke}-n\: \: \textrm{dari}\: \: \: y=\displaystyle \frac{1}{x} \: \: \textrm{adalah}.... \\ &\begin{array}{lll}\\ \textrm{a}.\quad \displaystyle n!\: .\: x^{-(n+1)} & \\ \textrm{b}.\quad \displaystyle (n+1)!\: .\: x^{-(n+1)}& \\ \textrm{c}.\quad \color{red}\displaystyle (-1)^{n}\: n!\: .\: x^{-(n+1)}\\ \textrm{d}.\quad (-1)^{n+1}\: n!\: .\: x^{-(n+1)}\\ \textrm{e}.\quad (-1)^{n+1}\: (n+1)!\: .\: x^{-(n+1)} \end{array}\\\\ &\textbf{Jawab}:\\ &\begin{array}{|c|c|l|}\hline \textrm{Fungsi}&y=\displaystyle \frac{1}{x}&\quad y=x^{-1}\\\hline y'=\displaystyle \frac{dy}{dx}&-x^{-2}&(-1)^{1}.1!.x^{-(1+1)}\\\hline y''=\displaystyle \frac{d^{2}y}{dx^{2}}&2x^{-3}&(-1)^{2}.2!.x^{-(2+1)}\\\hline y'''=\displaystyle \frac{d^{3}y}{dx^{3}}&-6x^{-4}&(-1)^{3}.3!.x^{-(3+1)}\\\hline y^{IV}=\displaystyle \frac{d^{4}y}{dx^{4}}&24x^{-5}&(-1)^{4}.4!.x^{-(4+1)}\\\hline y^{V}=\displaystyle \frac{d^{5}y}{dx^{5}}&\cdots &\quad \cdots \\\hline \vdots &\vdots &\quad \vdots \\\hline y^{n}=\displaystyle \frac{d^{n}y}{dx^{n}}&\cdots &\color{red}(-1)^{n}.n!.x^{-(n+1)}\\\hline \end{array} \end{array}$.
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