Questions: Find the derivative of f(x) = 2 / (3x).
f'(x) = -2 / (3x^2)
Transcript text: Find the derivative of $f(x)=\frac{2}{3 x}$.
$f^{\prime}(x)=\frac{-2}{3 x^{2}}$
Solution
Solution Steps
Step 1: Rewrite the Function with a Negative Exponent
Given the function \( f(x) = \frac{2}{3x} \), we can rewrite it to explicitly show the negative exponent:
\[ f(x) = 2 \cdot (3x)^{-1} \]
Step 2: Apply the Power Rule for Differentiation
Using the power rule for differentiation, which states that \(\frac{d}{dx} [x^n] = n \cdot x^{n-1}\), we differentiate the function:
\[ f'(x) = 2 \cdot \frac{d}{dx} [(3x)^{-1}] \]
Step 3: Differentiate the Inner Function
First, we differentiate the inner function \((3x)^{-1}\):
\[ \frac{d}{dx} [(3x)^{-1}] = -1 \cdot (3x)^{-2} \cdot 3 = -3 \cdot (3x)^{-2} \]
Step 4: Simplify the Derivative
Now, we multiply by the constant 2:
\[ f'(x) = 2 \cdot (-3) \cdot (3x)^{-2} = -2 \cdot (3x)^{-2} \]
Step 5: Simplify the Expression
Simplify the expression to match one of the provided options:
\[ f'(x) = \frac{-2}{3x^2} \]