given (f(x)=\frac{2}{x}), find (f(x)) using the limit definition of the derivative.\n\n(f(x)=)\n\nquestion…

given (f(x)=\frac{2}{x}), find (f(x)) using the limit definition of the derivative.\n\n(f(x)=)\n\nquestion help: video message instructor\n\nsubmit question jump to answer
Answer
Explanation:
Step1: Recall limit - definition of derivative
The limit - definition of the derivative is $f^{\prime}(x)=\lim_{h\rightarrow0}\frac{f(x + h)-f(x)}{h}$. Given $f(x)=\frac{2}{x}$, then $f(x + h)=\frac{2}{x + h}$.
Step2: Substitute into the formula
$\frac{f(x + h)-f(x)}{h}=\frac{\frac{2}{x + h}-\frac{2}{x}}{h}=\frac{\frac{2x-2(x + h)}{x(x + h)}}{h}$.
Step3: Simplify the numerator
$2x-2(x + h)=2x-2x-2h=-2h$. So, $\frac{\frac{2x - 2(x + h)}{x(x + h)}}{h}=\frac{\frac{-2h}{x(x + h)}}{h}$.
Step4: Simplify the complex - fraction
$\frac{\frac{-2h}{x(x + h)}}{h}=\frac{-2h}{x(x + h)}\cdot\frac{1}{h}=-\frac{2}{x(x + h)}$.
Step5: Take the limit as $h\rightarrow0$
$f^{\prime}(x)=\lim_{h\rightarrow0}-\frac{2}{x(x + h)}$. As $h\rightarrow0$, we get $f^{\prime}(x)=-\frac{2}{x^{2}}$.
Answer:
$-\frac{2}{x^{2}}$