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Derivative of log((2*x-1)/(x+2))

Function f() - derivative -N order at the point
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The solution

You have entered [src]
   /2*x - 1\
log|-------|
   \ x + 2 /
log(2x1x+2)\log{\left(\frac{2 x - 1}{x + 2} \right)}
log((2*x - 1)/(x + 2))
Detail solution
  1. Let u=2x1x+2u = \frac{2 x - 1}{x + 2}.

  2. The derivative of log(u)\log{\left(u \right)} is 1u\frac{1}{u}.

  3. Then, apply the chain rule. Multiply by ddx2x1x+2\frac{d}{d x} \frac{2 x - 1}{x + 2}:

    1. Apply the quotient rule, which is:

      ddxf(x)g(x)=f(x)ddxg(x)+g(x)ddxf(x)g2(x)\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(x)=2x1f{\left(x \right)} = 2 x - 1 and g(x)=x+2g{\left(x \right)} = x + 2.

      To find ddxf(x)\frac{d}{d x} f{\left(x \right)}:

      1. Differentiate 2x12 x - 1 term by term:

        1. The derivative of the constant 1-1 is zero.

        2. The derivative of a constant times a function is the constant times the derivative of the function.

          1. Apply the power rule: xx goes to 11

          So, the result is: 22

        The result is: 22

      To find ddxg(x)\frac{d}{d x} g{\left(x \right)}:

      1. Differentiate x+2x + 2 term by term:

        1. The derivative of the constant 22 is zero.

        2. Apply the power rule: xx goes to 11

        The result is: 11

      Now plug in to the quotient rule:

      5(x+2)2\frac{5}{\left(x + 2\right)^{2}}

    The result of the chain rule is:

    5(x+2)(x+2)2(2x1)\frac{5 \left(x + 2\right)}{\left(x + 2\right)^{2} \left(2 x - 1\right)}

  4. Now simplify:

    5(x+2)(2x1)\frac{5}{\left(x + 2\right) \left(2 x - 1\right)}


The answer is:

5(x+2)(2x1)\frac{5}{\left(x + 2\right) \left(2 x - 1\right)}

The graph
02468-8-6-4-2-1010-250250
The first derivative [src]
        /  2     2*x - 1 \
(x + 2)*|----- - --------|
        |x + 2          2|
        \        (x + 2) /
--------------------------
         2*x - 1          
(x+2)(2x+22x1(x+2)2)2x1\frac{\left(x + 2\right) \left(\frac{2}{x + 2} - \frac{2 x - 1}{\left(x + 2\right)^{2}}\right)}{2 x - 1}
The second derivative [src]
/    -1 + 2*x\ /    1        2    \
|2 - --------|*|- ----- - --------|
\     2 + x  / \  2 + x   -1 + 2*x/
-----------------------------------
              -1 + 2*x             
(22x1x+2)(22x11x+2)2x1\frac{\left(2 - \frac{2 x - 1}{x + 2}\right) \left(- \frac{2}{2 x - 1} - \frac{1}{x + 2}\right)}{2 x - 1}
The third derivative [src]
  /    -1 + 2*x\ /   1            4                2         \
2*|2 - --------|*|-------- + ----------- + ------------------|
  \     2 + x  / |       2             2   (-1 + 2*x)*(2 + x)|
                 \(2 + x)    (-1 + 2*x)                      /
--------------------------------------------------------------
                           -1 + 2*x                           
2(22x1x+2)(4(2x1)2+2(x+2)(2x1)+1(x+2)2)2x1\frac{2 \left(2 - \frac{2 x - 1}{x + 2}\right) \left(\frac{4}{\left(2 x - 1\right)^{2}} + \frac{2}{\left(x + 2\right) \left(2 x - 1\right)} + \frac{1}{\left(x + 2\right)^{2}}\right)}{2 x - 1}