\begin{frame} \frametitle{Logarithmic Differentiation} \begin{exampleblock}{} Differentiate \begin{talign} y = x^{\sqrt{x}} \end{talign} \pause The power rule does not apply: the exponent contains $x$! \pause\medskip We use logarithmic differentiation: \begin{talign} &\ln y = \ln \left(x^{\sqrt{x}}\right) = \mpause[1]{\sqrt{x} \cdot \ln x} \\ &\mpause[2]{ \frac{d}{dx} \ln y = \frac{d}{dx } \left( \sqrt{x} \cdot \ln x \right) }\\ &\mpause[3]{ \frac{1}{y}y' = \sqrt{x}\cdot \frac{1}{x} + \ln x \cdot \frac{1}{2\sqrt{x}} }\\ &\mpause[4]{ y' = y\left( \frac{1}{\sqrt{x}} + \frac{\ln x}{2\sqrt{x}} \right) } \mpause[5]{= y\left( \frac{2+ \ln x}{2\sqrt{x}} \right) } \mpause[6]{= x^{\sqrt{x}} \left( \frac{2+ \ln x}{2\sqrt{x}} \right) } \end{talign} \pause\pause\pause\pause\pause\pause \end{exampleblock} \pause\medskip Alternative: \quad $x^{\sqrt{x}} \mpause[1]{ = (e^{\ln x})^{\sqrt{x}}} \mpause[2]{ = e^{\ln x \cdot \sqrt{x}}}$\quad \pause\pause\pause now use chain rule \bigskip \end{frame}