Mister Exam

Derivative of ln(tgx/2)-x/sinx

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

The graph:

from to

Piecewise:

The solution

You have entered [src]
   /tan(x)\     x   
log|------| - ------
   \  2   /   sin(x)
xsin(x)+log(tan(x)2)- \frac{x}{\sin{\left(x \right)}} + \log{\left(\frac{\tan{\left(x \right)}}{2} \right)}
log(tan(x)/2) - x/sin(x)
Detail solution
  1. Differentiate xsin(x)+log(tan(x)2)- \frac{x}{\sin{\left(x \right)}} + \log{\left(\frac{\tan{\left(x \right)}}{2} \right)} term by term:

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

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

    3. Then, apply the chain rule. Multiply by ddxtan(x)2\frac{d}{d x} \frac{\tan{\left(x \right)}}{2}:

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

        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)}}

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

      The result of the chain rule is:

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

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

      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)=xf{\left(x \right)} = x 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. Apply the power rule: xx goes to 11

        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:

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

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

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

  2. Now simplify:

    2(xcos(2x)+x+2sin(x)sin(2x))cos(x)cos(3x)\frac{2 \left(x \cos{\left(2 x \right)} + x + 2 \sin{\left(x \right)} - \sin{\left(2 x \right)}\right)}{\cos{\left(x \right)} - \cos{\left(3 x \right)}}


The answer is:

2(xcos(2x)+x+2sin(x)sin(2x))cos(x)cos(3x)\frac{2 \left(x \cos{\left(2 x \right)} + x + 2 \sin{\left(x \right)} - \sin{\left(2 x \right)}\right)}{\cos{\left(x \right)} - \cos{\left(3 x \right)}}

The graph
02468-8-6-4-2-1010-5000050000
The first derivative [src]
             /       2   \           
             |1   tan (x)|           
           2*|- + -------|           
    1        \2      2   /   x*cos(x)
- ------ + --------------- + --------
  sin(x)        tan(x)          2    
                             sin (x) 
xcos(x)sin2(x)+2(tan2(x)2+12)tan(x)1sin(x)\frac{x \cos{\left(x \right)}}{\sin^{2}{\left(x \right)}} + \frac{2 \left(\frac{\tan^{2}{\left(x \right)}}{2} + \frac{1}{2}\right)}{\tan{\left(x \right)}} - \frac{1}{\sin{\left(x \right)}}
The second derivative [src]
                                      2                         
                         /       2   \                      2   
         2        x      \1 + tan (x)/    2*cos(x)   2*x*cos (x)
2 + 2*tan (x) - ------ - -------------- + -------- - -----------
                sin(x)         2             2            3     
                            tan (x)       sin (x)      sin (x)  
xsin(x)2xcos2(x)sin3(x)(tan2(x)+1)2tan2(x)+2tan2(x)+2+2cos(x)sin2(x)- \frac{x}{\sin{\left(x \right)}} - \frac{2 x \cos^{2}{\left(x \right)}}{\sin^{3}{\left(x \right)}} - \frac{\left(\tan^{2}{\left(x \right)} + 1\right)^{2}}{\tan^{2}{\left(x \right)}} + 2 \tan^{2}{\left(x \right)} + 2 + \frac{2 \cos{\left(x \right)}}{\sin^{2}{\left(x \right)}}
The third derivative [src]
                                      2                  3                                                    
                2        /       2   \      /       2   \                                                 3   
    3      6*cos (x)   4*\1 + tan (x)/    2*\1 + tan (x)/      /       2   \          5*x*cos(x)   6*x*cos (x)
- ------ - --------- - ---------------- + ---------------- + 4*\1 + tan (x)/*tan(x) + ---------- + -----------
  sin(x)       3            tan(x)               3                                        2             4     
            sin (x)                           tan (x)                                  sin (x)       sin (x)  
5xcos(x)sin2(x)+6xcos3(x)sin4(x)+2(tan2(x)+1)3tan3(x)4(tan2(x)+1)2tan(x)+4(tan2(x)+1)tan(x)3sin(x)6cos2(x)sin3(x)\frac{5 x \cos{\left(x \right)}}{\sin^{2}{\left(x \right)}} + \frac{6 x \cos^{3}{\left(x \right)}}{\sin^{4}{\left(x \right)}} + \frac{2 \left(\tan^{2}{\left(x \right)} + 1\right)^{3}}{\tan^{3}{\left(x \right)}} - \frac{4 \left(\tan^{2}{\left(x \right)} + 1\right)^{2}}{\tan{\left(x \right)}} + 4 \left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)} - \frac{3}{\sin{\left(x \right)}} - \frac{6 \cos^{2}{\left(x \right)}}{\sin^{3}{\left(x \right)}}