Question 39

Maths Question: 

$\int{\frac{1}{x}{{({{\log }_{e}}x)}^{3}}dx}$

Maths Solution: 

$\begin{align}  & \int{\frac{1}{x}{{({{\log }_{e}}x)}^{3}}dx} \\ & \text{Let }u={{\log }_{e}}x \\ & \frac{du}{dx}=\frac{1}{x},\text{  }dx=xdu \\ & \int{\frac{1}{x}{{({{\log }_{e}}x)}^{3}}dx}=\int{\frac{1}{x}{{(u)}^{3}}xdu}=\int{{{u}^{3}}du} \\ & \int{\frac{1}{x}{{({{\log }_{e}}x)}^{3}}dx}=\frac{{{u}^{4}}}{4}+C=\frac{1}{4}{{({{\log }_{e}}x)}^{4}}+C \\\end{align}$

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