Q. \[ \frac{d}{dx}\left(x^x\right) \]
Answer
Use logarithmic differentiation. Let \(y=x^x\) (assume \(x>0\)). Take the natural log:
\[
\ln y = \ln(x^x)=x\ln x
\]
Differentiate both sides:
\[
\frac{1}{y}\frac{dy}{dx}=\frac{d}{dx}\bigl(x\ln x\bigr)=\ln x+1
\]
Solve for \(\frac{dy}{dx}\) using \(y=x^x\):
\[
\frac{dy}{dx}=x^x(\ln x+1)
\]
Final result: \(\displaystyle \frac{d}{dx}\left(x^x\right)=x^x(\ln x+1)\).
Detailed Explanation
We want to find the derivative of \(y = x^x\). Because the variable appears both as the base and the exponent, we cannot use the usual power rule directly. Instead, we use logarithmic differentiation.
Step 1: Define the function and take natural logs
Let
\[ y = x^x \]
Take the natural logarithm of both sides:
\[ \ln(y) = \ln(x^x) \]
Using the log rule \(\ln(a^b)=b\ln(a)\), we get:
\[ \ln(y) = x\ln(x) \]
Step 2: Differentiate both sides
Differentiating the left side with respect to \(x\):
\[ \frac{d}{dx}\left(\ln(y)\right) = \frac{1}{y}\frac{dy}{dx} \]
Differentiating the right side:
\[ \frac{d}{dx}\left(x\ln(x)\right) \]
This is a product \(x \cdot \ln(x)\), so we use the product rule:
\[ \frac{d}{dx}\left(x\ln(x)\right) = 1\cdot \ln(x) + x\cdot \frac{1}{x} \]
Simplify:
\[ \frac{d}{dx}\left(x\ln(x)\right) = \ln(x) + 1 \]
Step 3: Set the derivatives equal
So we have:
\[ \frac{1}{y}\frac{dy}{dx} = \ln(x) + 1 \]
Step 4: Solve for \(\frac{dy}{dx}\)
Multiply both sides by \(y\):
\[ \frac{dy}{dx} = y\left(\ln(x) + 1\right) \]
Recall that \(y = x^x\). Substitute back:
\[ \frac{dy}{dx} = x^x\left(\ln(x) + 1\right) \]
Final Answer
\[ \frac{d}{dx}\left(x^x\right) = x^x\left(\ln(x) + 1\right) \]
Graph
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