Questions: Use logarithmic differentiation to find the derivative of y with respect to the given independent variable.
y=(sin 5 x)^(7 x)
dy/dx=
Transcript text: Use logarithmic differentiation to find the derivative of $y$ with respect to the given independent variable.
\[
\begin{array}{r}
y=(\sin 5 x)^{7 x} \\
\frac{d y}{d x}=\square
\end{array}
\]
$\square$
Solution
Solution Steps
To find the derivative of \( y = (\sin 5x)^{7x} \) using logarithmic differentiation, follow these steps:
Take the natural logarithm of both sides to simplify the expression.
Differentiate both sides with respect to \( x \).
Solve for \( \frac{dy}{dx} \).
Step 1: Define the Function
We start with the function given by
\[
y = (\sin(5x))^{7x}.
\]
Step 2: Take the Natural Logarithm
Taking the natural logarithm of both sides, we have:
\[
\ln(y) = 7x \ln(\sin(5x)).
\]
Step 3: Differentiate Both Sides
Differentiating both sides with respect to \( x \):
\[
\frac{d}{dx}(\ln(y)) = \frac{d}{dx}(7x \ln(\sin(5x))).
\]
Using the product rule and chain rule, we find:
\[
\frac{1}{y} \frac{dy}{dx} = 7 \ln(\sin(5x)) + 7x \cdot \frac{5 \cos(5x)}{\sin(5x)}.
\]
Step 4: Solve for \(\frac{dy}{dx}\)
Multiplying both sides by \( y \) gives:
\[
\frac{dy}{dx} = y \left( 7 \ln(\sin(5x)) + 35x \frac{\cos(5x)}{\sin(5x)} \right).
\]
Substituting back \( y = (\sin(5x))^{7x} \):
\[
\frac{dy}{dx} = (\sin(5x))^{7x} \left( 7 \ln(\sin(5x)) + 35x \frac{\cos(5x)}{\sin(5x)} \right).
\]
Step 5: Simplify the Expression
The expression can be simplified to:
\[
\frac{dy}{dx} = 7 \left( 5x \cos(5x) + \ln(\sin(5x)) \sin(5x) \right) (\sin(5x))^{7x - 1}.
\]
Final Answer
Thus, the derivative of \( y \) with respect to \( x \) is:
\[
\boxed{\frac{dy}{dx} = 7 \left( 5x \cos(5x) + \ln(\sin(5x)) \sin(5x) \right) (\sin(5x))^{7x - 1}}.
\]