How can I develop ln(x) into a series for x >= 1 in fluid dynamics?

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The discussion focuses on developing the natural logarithm function, specifically $\mathrm{ln}(x)$, into a series for values where $x \geq 1$, relevant to fluid dynamics applications. The user references existing series expansions for $\mathrm{ln}(x)$ and $\mathrm{ln}(x+1)$, which are valid under different conditions. The proposed solution involves deriving the series for $\ln(1+x)$ and $\ln(1-x)$, then combining these to obtain the series for $\ln\left(\frac{1+x}{1-x}\right)$. This approach is crucial for analyzing non-dimensional coordinates in annular tube flow.

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This discussion is beneficial for fluid dynamics engineers, mathematicians, and researchers involved in modeling flow in annular tubes, as well as anyone interested in the mathematical properties of logarithmic functions.

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I need to develop $\mathrm{ln}(x)$ into series, where $x \geq 1$, and I don`t know how? In literature I only found series of $\mathrm{ln}(x)$, where:

1. $|x-1| \leq 1 \land x \neq 0$, $ \,\,\,\,\, \mathrm{ln}(x) = x - 1 - \dfrac{(x-1)^2}{2} + ...$ 2. $|x| \leq 1 \land x \neq -1$, $ \,\,\,\,\, \mathrm{ln}(x+1) = x - \dfrac{x^2}{2}+ ...$

My problem is problem in area of fluid dynamics, and $x$ is non-dimensional coordinate and it signifies radial coordinate of annular tube (it starts in the center of the tube). At the wall of inner tube $x=1$, and at the wall of outer tube it only can be larger (and values are not limited), because of that I need to fulfill a condition $x \geq 1$, for developing $\mathrm{ln}(x)$ into series.
 
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Write series for $$\ln (1+x)$$ and $$\ln (1-x)$$. Then subtract second from the first one and you'll obtain the series for $$\ln \left( \frac{1+x}{1-x} \right) $$, which gives you one possible series.
 

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