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Lösung 1.2:2d

Aus Online Mathematik Brückenkurs 2

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We can see the expression as "ln of something",


ln,

where "something" is lnx.

Because we have a compound expression, we use the chain rule and obtain, roughly speaking, the outer derivative multiplied by the inner derivative,


\displaystyle \frac{d}{dx}\ln \left\{ \left. \ln x \right\} \right.=\frac{1}{\ln x}\centerdot \left( \left\{ \left. \ln x \right\} \right. \right)^{\prime }


where the first factor on the right-hand side \displaystyle \frac{1}{\ln x} is the outer derivative of \displaystyle \ln \left\{ \left. \ln x \right\} \right. and the other factor \displaystyle \left( \left\{ \left. \ln x \right\} \right. \right)^{\prime } is the inner derivative. Thus, we get


\displaystyle \frac{d}{dx}\ln \left\{ \left. \ln x \right\} \right.=\frac{1}{\ln x}\centerdot \frac{1}{x}=\frac{1}{x\ln x}