Mister Exam

Derivative of y=sin(x)/ln(x)

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

The graph:

from to

Piecewise:

The solution

You have entered [src]
sin(x)
------
log(x)
sin(x)log(x)\frac{\sin{\left(x \right)}}{\log{\left(x \right)}}
d /sin(x)\
--|------|
dx\log(x)/
ddxsin(x)log(x)\frac{d}{d x} \frac{\sin{\left(x \right)}}{\log{\left(x \right)}}
Detail solution
  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)=sin(x)f{\left(x \right)} = \sin{\left(x \right)} and g(x)=log(x)g{\left(x \right)} = \log{\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 log(x)\log{\left(x \right)} is 1x\frac{1}{x}.

    Now plug in to the quotient rule:

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

  2. Now simplify:

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


The answer is:

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

The graph
02468-8-6-4-2-1010-200100
The first derivative [src]
cos(x)     sin(x) 
------ - ---------
log(x)        2   
         x*log (x)
cos(x)log(x)sin(x)xlog(x)2\frac{\cos{\left(x \right)}}{\log{\left(x \right)}} - \frac{\sin{\left(x \right)}}{x \log{\left(x \right)}^{2}}
The second derivative [src]
                     /      2   \       
                     |1 + ------|*sin(x)
          2*cos(x)   \    log(x)/       
-sin(x) - -------- + -------------------
          x*log(x)         2            
                          x *log(x)     
----------------------------------------
                 log(x)                 
sin(x)2cos(x)xlog(x)+(1+2log(x))sin(x)x2log(x)log(x)\frac{- \sin{\left(x \right)} - \frac{2 \cos{\left(x \right)}}{x \log{\left(x \right)}} + \frac{\left(1 + \frac{2}{\log{\left(x \right)}}\right) \sin{\left(x \right)}}{x^{2} \log{\left(x \right)}}}{\log{\left(x \right)}}
The third derivative [src]
                       /      3         3   \                               
                     2*|1 + ------ + -------|*sin(x)     /      2   \       
                       |    log(x)      2   |          3*|1 + ------|*cos(x)
          3*sin(x)     \             log (x)/            \    log(x)/       
-cos(x) + -------- - ------------------------------- + ---------------------
          x*log(x)               3                            2             
                                x *log(x)                    x *log(x)      
----------------------------------------------------------------------------
                                   log(x)                                   
cos(x)+3sin(x)xlog(x)+3(1+2log(x))cos(x)x2log(x)2(1+3log(x)+3log(x)2)sin(x)x3log(x)log(x)\frac{- \cos{\left(x \right)} + \frac{3 \sin{\left(x \right)}}{x \log{\left(x \right)}} + \frac{3 \cdot \left(1 + \frac{2}{\log{\left(x \right)}}\right) \cos{\left(x \right)}}{x^{2} \log{\left(x \right)}} - \frac{2 \cdot \left(1 + \frac{3}{\log{\left(x \right)}} + \frac{3}{\log{\left(x \right)}^{2}}\right) \sin{\left(x \right)}}{x^{3} \log{\left(x \right)}}}{\log{\left(x \right)}}
The graph
Derivative of y=sin(x)/ln(x)