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y=1/ctg^2x+1/3(ctgx)

Derivative of y=1/ctg^2x+1/3(ctgx)

Function f() - derivative -N order at the point
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     1      cot(x)
1*------- + ------
     2        3   
  cot (x)         
cot(x)3+11cot2(x)\frac{\cot{\left(x \right)}}{3} + 1 \cdot \frac{1}{\cot^{2}{\left(x \right)}}
d /     1      cot(x)\
--|1*------- + ------|
dx|     2        3   |
  \  cot (x)         /
ddx(cot(x)3+11cot2(x))\frac{d}{d x} \left(\frac{\cot{\left(x \right)}}{3} + 1 \cdot \frac{1}{\cot^{2}{\left(x \right)}}\right)
Detail solution
  1. Differentiate cot(x)3+11cot2(x)\frac{\cot{\left(x \right)}}{3} + 1 \cdot \frac{1}{\cot^{2}{\left(x \right)}} term by term:

    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)=1f{\left(x \right)} = 1 and g(x)=cot2(x)g{\left(x \right)} = \cot^{2}{\left(x \right)}.

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

      1. The derivative of the constant 11 is zero.

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

      1. Let u=cot(x)u = \cot{\left(x \right)}.

      2. Apply the power rule: u2u^{2} goes to 2u2 u

      3. Then, apply the chain rule. Multiply by ddxcot(x)\frac{d}{d x} \cot{\left(x \right)}:

        1. There are multiple ways to do this derivative.

          Method #1

          1. Rewrite the function to be differentiated:

            cot(x)=1tan(x)\cot{\left(x \right)} = \frac{1}{\tan{\left(x \right)}}

          2. Let u=tan(x)u = \tan{\left(x \right)}.

          3. Apply the power rule: 1u\frac{1}{u} goes to 1u2- \frac{1}{u^{2}}

          4. Then, apply the chain rule. Multiply by ddxtan(x)\frac{d}{d x} \tan{\left(x \right)}:

            1. Rewrite the function to be differentiated:

              tan(x)=sin(x)cos(x)\tan{\left(x \right)} = \frac{\sin{\left(x \right)}}{\cos{\left(x \right)}}

            2. 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)=sin(x)f{\left(x \right)} = \sin{\left(x \right)} and g(x)=cos(x)g{\left(x \right)} = \cos{\left(x \right)}.

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

              1. The derivative of sine is cosine:

                ddxsin(x)=cos(x)\frac{d}{d x} \sin{\left(x \right)} = \cos{\left(x \right)}

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

              1. The derivative of cosine is negative sine:

                ddxcos(x)=sin(x)\frac{d}{d x} \cos{\left(x \right)} = - \sin{\left(x \right)}

              Now plug in to the quotient rule:

              sin2(x)+cos2(x)cos2(x)\frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}}

            The result of the chain rule is:

            sin2(x)+cos2(x)cos2(x)tan2(x)- \frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)} \tan^{2}{\left(x \right)}}

          Method #2

          1. Rewrite the function to be differentiated:

            cot(x)=cos(x)sin(x)\cot{\left(x \right)} = \frac{\cos{\left(x \right)}}{\sin{\left(x \right)}}

          2. 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)=cos(x)f{\left(x \right)} = \cos{\left(x \right)} and g(x)=sin(x)g{\left(x \right)} = \sin{\left(x \right)}.

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

            1. The derivative of cosine is negative sine:

              ddxcos(x)=sin(x)\frac{d}{d x} \cos{\left(x \right)} = - \sin{\left(x \right)}

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

            1. The derivative of sine is cosine:

              ddxsin(x)=cos(x)\frac{d}{d x} \sin{\left(x \right)} = \cos{\left(x \right)}

            Now plug in to the quotient rule:

            sin2(x)cos2(x)sin2(x)\frac{- \sin^{2}{\left(x \right)} - \cos^{2}{\left(x \right)}}{\sin^{2}{\left(x \right)}}

        The result of the chain rule is:

        2(sin2(x)+cos2(x))cot(x)cos2(x)tan2(x)- \frac{2 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right) \cot{\left(x \right)}}{\cos^{2}{\left(x \right)} \tan^{2}{\left(x \right)}}

      Now plug in to the quotient rule:

      2(sin2(x)+cos2(x))cos2(x)tan2(x)cot3(x)\frac{2 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right)}{\cos^{2}{\left(x \right)} \tan^{2}{\left(x \right)} \cot^{3}{\left(x \right)}}

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

      1. ddxcot(x)=1sin2(x)\frac{d}{d x} \cot{\left(x \right)} = - \frac{1}{\sin^{2}{\left(x \right)}}

      So, the result is: sin2(x)+cos2(x)3cos2(x)tan2(x)- \frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{3 \cos^{2}{\left(x \right)} \tan^{2}{\left(x \right)}}

    The result is: sin2(x)+cos2(x)3cos2(x)tan2(x)+2(sin2(x)+cos2(x))cos2(x)tan2(x)cot3(x)- \frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{3 \cos^{2}{\left(x \right)} \tan^{2}{\left(x \right)}} + \frac{2 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right)}{\cos^{2}{\left(x \right)} \tan^{2}{\left(x \right)} \cot^{3}{\left(x \right)}}

  2. Now simplify:

    2sin(x)cos3(x)13sin2(x)\frac{2 \sin{\left(x \right)}}{\cos^{3}{\left(x \right)}} - \frac{1}{3 \sin^{2}{\left(x \right)}}


The answer is:

2sin(x)cos3(x)13sin2(x)\frac{2 \sin{\left(x \right)}}{\cos^{3}{\left(x \right)}} - \frac{1}{3 \sin^{2}{\left(x \right)}}

The graph
02468-8-6-4-2-1010-100000100000
The first derivative [src]
         2                2   
  1   cot (x)   -2 - 2*cot (x)
- - - ------- - --------------
  3      3                2   
                cot(x)*cot (x)
2cot2(x)2cot(x)cot2(x)cot2(x)313- \frac{- 2 \cot^{2}{\left(x \right)} - 2}{\cot{\left(x \right)} \cot^{2}{\left(x \right)}} - \frac{\cot^{2}{\left(x \right)}}{3} - \frac{1}{3}
The second derivative [src]
  /       2   \ /              /       2   \         \
  |1   cot (x)| |     6      9*\1 + cot (x)/         |
2*|- + -------|*|- ------- + --------------- + cot(x)|
  \3      3   / |     2             4                |
                \  cot (x)       cot (x)             /
2(cot2(x)3+13)(9(cot2(x)+1)cot4(x)+cot(x)6cot2(x))2 \left(\frac{\cot^{2}{\left(x \right)}}{3} + \frac{1}{3}\right) \left(\frac{9 \left(\cot^{2}{\left(x \right)} + 1\right)}{\cot^{4}{\left(x \right)}} + \cot{\left(x \right)} - \frac{6}{\cot^{2}{\left(x \right)}}\right)
The third derivative [src]
                /                                                             2\
  /       2   \ |                             /       2   \      /       2   \ |
  |1   cot (x)| |          2        12     48*\1 + cot (x)/   36*\1 + cot (x)/ |
2*|- + -------|*|-1 - 3*cot (x) + ------ - ---------------- + -----------------|
  \3      3   / |                 cot(x)          3                   5        |
                \                              cot (x)             cot (x)     /
2(cot2(x)3+13)(36(cot2(x)+1)2cot5(x)48(cot2(x)+1)cot3(x)3cot2(x)1+12cot(x))2 \left(\frac{\cot^{2}{\left(x \right)}}{3} + \frac{1}{3}\right) \left(\frac{36 \left(\cot^{2}{\left(x \right)} + 1\right)^{2}}{\cot^{5}{\left(x \right)}} - \frac{48 \left(\cot^{2}{\left(x \right)} + 1\right)}{\cot^{3}{\left(x \right)}} - 3 \cot^{2}{\left(x \right)} - 1 + \frac{12}{\cot{\left(x \right)}}\right)
The graph
Derivative of y=1/ctg^2x+1/3(ctgx)