Derivative of ln((x-1)/(x+1))

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   /x - 1\
log|-----|
   \x + 1/

$$\log{\left(\frac{x - 1}{x + 1} \right)}$$

log((x - 1)/(x + 1))

Detail solution

Let $u = \frac{x - 1}{x + 1}$ .
The derivative of $\log{\left(u \right)}$ is $\frac{1}{u}$ .
Then, apply the chain rule. Multiply by $\frac{d}{d x} \frac{x - 1}{x + 1}$ :
1. Apply the quotient rule, which is:
  
  $\frac{d}{d x} \frac{f{\left(x \right)}}{g{\left(x \right)}} = \frac{- f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}}{g^{2}{\left(x \right)}}$
  
  $f{\left(x \right)} = x - 1$ and $g{\left(x \right)} = x + 1$ .
  
  To find $\frac{d}{d x} f{\left(x \right)}$ :
  1. Differentiate $x - 1$ term by term:
    1. The derivative of the constant $-1$ is zero.
    2. Apply the power rule: $x$ goes to $1$
    The result is: $1$
  To find $\frac{d}{d x} g{\left(x \right)}$ :
  1. Differentiate $x + 1$ term by term:
    1. The derivative of the constant $1$ is zero.
    2. Apply the power rule: $x$ goes to $1$
    The result is: $1$
  Now plug in to the quotient rule:
  
  $\frac{2}{\left(x + 1\right)^{2}}$
The result of the chain rule is:

$\frac{2 \left(x + 1\right)}{\left(x - 1\right) \left(x + 1\right)^{2}}$
Now simplify:

$\frac{2}{x^{2} - 1}$

The answer is:

$\frac{2}{x^{2} - 1}$

The graph

Plot the graph f(x)

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The first derivative [src]

        /  1      x - 1  \
(x + 1)*|----- - --------|
        |x + 1          2|
        \        (x + 1) /
--------------------------
          x - 1

$$\frac{\left(x + 1\right) \left(- \frac{x - 1}{\left(x + 1\right)^{2}} + \frac{1}{x + 1}\right)}{x - 1}$$

Simplify

The second derivative [src]

/     -1 + x\ /  1       1   \
|-1 + ------|*|----- + ------|
\     1 + x / \1 + x   -1 + x/
------------------------------
            -1 + x

$$\frac{\left(\frac{x - 1}{x + 1} - 1\right) \left(\frac{1}{x + 1} + \frac{1}{x - 1}\right)}{x - 1}$$

Simplify

The third derivative [src]

  /     -1 + x\ /     1           1              1        \
2*|-1 + ------|*|- -------- - --------- - ----------------|
  \     1 + x / |         2           2   (1 + x)*(-1 + x)|
                \  (1 + x)    (-1 + x)                    /
-----------------------------------------------------------
                           -1 + x

$$\frac{2 \left(\frac{x - 1}{x + 1} - 1\right) \left(- \frac{1}{\left(x + 1\right)^{2}} - \frac{1}{\left(x - 1\right) \left(x + 1\right)} - \frac{1}{\left(x - 1\right)^{2}}\right)}{x - 1}$$

Simplify

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Derivative of ln((x-1)/(x+1))

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