Questions: Find the derivative of y with respect to x.
y = ln (1-x)/(x+5)^6
Transcript text: Question 8
Find the derivative of $y$ with respect to $x$.
\[
y=\ln \frac{1-x}{(x+5)^{6}}
\]
Solution
Solution Steps
To find the derivative of \( y \) with respect to \( x \) for the given function \( y = \ln \frac{1-x}{(x+5)^6} \), we can use the properties of logarithms and the chain rule. First, simplify the logarithmic expression using the properties of logarithms, then differentiate the resulting expression.
Step 1: Simplify the Logarithmic Expression
Given the function:
\[
y = \ln \left( \frac{1-x}{(x+5)^6} \right)
\]
We can use the properties of logarithms to simplify:
\[
y = \ln(1-x) - \ln((x+5)^6)
\]
\[
y = \ln(1-x) - 6\ln(x+5)
\]
Step 2: Differentiate the Simplified Expression
Differentiate \( y \) with respect to \( x \):
\[
\frac{dy}{dx} = \frac{d}{dx} \left( \ln(1-x) - 6\ln(x+5) \right)
\]
Using the chain rule:
\[
\frac{dy}{dx} = \frac{d}{dx} \ln(1-x) - 6 \frac{d}{dx} \ln(x+5)
\]
\[
\frac{dy}{dx} = \frac{-1}{1-x} - 6 \cdot \frac{1}{x+5}
\]
Step 3: Combine and Simplify the Derivative
Combine the terms:
\[
\frac{dy}{dx} = \frac{-1}{1-x} - \frac{6}{x+5}
\]
Find a common denominator:
\[
\frac{dy}{dx} = \frac{-(x+5) - 6(1-x)}{(1-x)(x+5)}
\]
Simplify the numerator:
\[
\frac{dy}{dx} = \frac{-x-5 - 6 + 6x}{(1-x)(x+5)}
\]
\[
\frac{dy}{dx} = \frac{5x - 11}{(1-x)(x+5)}
\]
Final Answer
The derivative of \( y \) with respect to \( x \) is:
\[
\boxed{\frac{5x - 11}{(1-x)(x+5)}}
\]