Mister Exam

Derivative of tg(ln^3x)

Function f() - derivative -N order at the point
v

The graph:

from to

Piecewise:

The solution

You have entered [src]
   /   3   \
tan\log (x)/
tan(log(x)3)\tan{\left(\log{\left(x \right)}^{3} \right)}
d /   /   3   \\
--\tan\log (x)//
dx              
ddxtan(log(x)3)\frac{d}{d x} \tan{\left(\log{\left(x \right)}^{3} \right)}
Detail solution
  1. Rewrite the function to be differentiated:

    tan(log(x)3)=sin(log(x)3)cos(log(x)3)\tan{\left(\log{\left(x \right)}^{3} \right)} = \frac{\sin{\left(\log{\left(x \right)}^{3} \right)}}{\cos{\left(\log{\left(x \right)}^{3} \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(log(x)3)f{\left(x \right)} = \sin{\left(\log{\left(x \right)}^{3} \right)} and g(x)=cos(log(x)3)g{\left(x \right)} = \cos{\left(\log{\left(x \right)}^{3} \right)}.

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

    1. Let u=log(x)3u = \log{\left(x \right)}^{3}.

    2. The derivative of sine is cosine:

      ddusin(u)=cos(u)\frac{d}{d u} \sin{\left(u \right)} = \cos{\left(u \right)}

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

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

      2. Apply the power rule: u3u^{3} goes to 3u23 u^{2}

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

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

        The result of the chain rule is:

        3log(x)2x\frac{3 \log{\left(x \right)}^{2}}{x}

      The result of the chain rule is:

      3log(x)2cos(log(x)3)x\frac{3 \log{\left(x \right)}^{2} \cos{\left(\log{\left(x \right)}^{3} \right)}}{x}

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

    1. Let u=log(x)3u = \log{\left(x \right)}^{3}.

    2. The derivative of cosine is negative sine:

      dducos(u)=sin(u)\frac{d}{d u} \cos{\left(u \right)} = - \sin{\left(u \right)}

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

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

      2. Apply the power rule: u3u^{3} goes to 3u23 u^{2}

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

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

        The result of the chain rule is:

        3log(x)2x\frac{3 \log{\left(x \right)}^{2}}{x}

      The result of the chain rule is:

      3log(x)2sin(log(x)3)x- \frac{3 \log{\left(x \right)}^{2} \sin{\left(\log{\left(x \right)}^{3} \right)}}{x}

    Now plug in to the quotient rule:

    3log(x)2sin2(log(x)3)x+3log(x)2cos2(log(x)3)xcos2(log(x)3)\frac{\frac{3 \log{\left(x \right)}^{2} \sin^{2}{\left(\log{\left(x \right)}^{3} \right)}}{x} + \frac{3 \log{\left(x \right)}^{2} \cos^{2}{\left(\log{\left(x \right)}^{3} \right)}}{x}}{\cos^{2}{\left(\log{\left(x \right)}^{3} \right)}}

  3. Now simplify:

    3log(x)2xcos2(log(x)3)\frac{3 \log{\left(x \right)}^{2}}{x \cos^{2}{\left(\log{\left(x \right)}^{3} \right)}}


The answer is:

3log(x)2xcos2(log(x)3)\frac{3 \log{\left(x \right)}^{2}}{x \cos^{2}{\left(\log{\left(x \right)}^{3} \right)}}

The graph
02468-8-6-4-2-1010-2000020000
The first derivative [src]
     2    /       2/   3   \\
3*log (x)*\1 + tan \log (x)//
-----------------------------
              x              
3(tan2(log(x)3)+1)log(x)2x\frac{3 \left(\tan^{2}{\left(\log{\left(x \right)}^{3} \right)} + 1\right) \log{\left(x \right)}^{2}}{x}
The second derivative [src]
  /       2/   3   \\ /                  3       /   3   \\       
3*\1 + tan \log (x)//*\2 - log(x) + 6*log (x)*tan\log (x)//*log(x)
------------------------------------------------------------------
                                 2                                
                                x                                 
3(tan2(log(x)3)+1)(6log(x)3tan(log(x)3)log(x)+2)log(x)x2\frac{3 \left(\tan^{2}{\left(\log{\left(x \right)}^{3} \right)} + 1\right) \left(6 \log{\left(x \right)}^{3} \tan{\left(\log{\left(x \right)}^{3} \right)} - \log{\left(x \right)} + 2\right) \log{\left(x \right)}}{x^{2}}
The third derivative [src]
  /       2/   3   \\ /       2                      4       /   3   \        6    /       2/   3   \\         3       /   3   \         6       2/   3   \\
6*\1 + tan \log (x)//*\1 + log (x) - 3*log(x) - 9*log (x)*tan\log (x)/ + 9*log (x)*\1 + tan \log (x)// + 18*log (x)*tan\log (x)/ + 18*log (x)*tan \log (x)//
------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              3                                                                             
                                                                             x                                                                              
6(tan2(log(x)3)+1)(18log(x)6tan2(log(x)3)+9(tan2(log(x)3)+1)log(x)69log(x)4tan(log(x)3)+18log(x)3tan(log(x)3)+log(x)23log(x)+1)x3\frac{6 \left(\tan^{2}{\left(\log{\left(x \right)}^{3} \right)} + 1\right) \left(18 \log{\left(x \right)}^{6} \tan^{2}{\left(\log{\left(x \right)}^{3} \right)} + 9 \left(\tan^{2}{\left(\log{\left(x \right)}^{3} \right)} + 1\right) \log{\left(x \right)}^{6} - 9 \log{\left(x \right)}^{4} \tan{\left(\log{\left(x \right)}^{3} \right)} + 18 \log{\left(x \right)}^{3} \tan{\left(\log{\left(x \right)}^{3} \right)} + \log{\left(x \right)}^{2} - 3 \log{\left(x \right)} + 1\right)}{x^{3}}
The graph
Derivative of tg(ln^3x)