Mister Exam

Derivative of y=tgx/sinx-cosx

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

The graph:

from to

Piecewise:

The solution

You have entered [src]
tan(x)         
------ - cos(x)
sin(x)         
cos(x)+tan(x)sin(x)- \cos{\left(x \right)} + \frac{\tan{\left(x \right)}}{\sin{\left(x \right)}}
tan(x)/sin(x) - cos(x)
Detail solution
  1. Differentiate cos(x)+tan(x)sin(x)- \cos{\left(x \right)} + \frac{\tan{\left(x \right)}}{\sin{\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)=tan(x)f{\left(x \right)} = \tan{\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. 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)}}

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

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

      1. The derivative of cosine is negative sine:

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

      So, the result is: sin(x)\sin{\left(x \right)}

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

  2. Now simplify:

    (1+1cos2(x))sin(x)\left(1 + \frac{1}{\cos^{2}{\left(x \right)}}\right) \sin{\left(x \right)}


The answer is:

(1+1cos2(x))sin(x)\left(1 + \frac{1}{\cos^{2}{\left(x \right)}}\right) \sin{\left(x \right)}

The graph
02468-8-6-4-2-1010-20002000
The first derivative [src]
       2                            
1 + tan (x)   cos(x)*tan(x)         
----------- - ------------- + sin(x)
   sin(x)           2               
                 sin (x)            
tan2(x)+1sin(x)+sin(x)cos(x)tan(x)sin2(x)\frac{\tan^{2}{\left(x \right)} + 1}{\sin{\left(x \right)}} + \sin{\left(x \right)} - \frac{\cos{\left(x \right)} \tan{\left(x \right)}}{\sin^{2}{\left(x \right)}}
The second derivative [src]
           /       2   \               2               /       2   \                
tan(x)   2*\1 + tan (x)/*cos(x)   2*cos (x)*tan(x)   2*\1 + tan (x)/*tan(x)         
------ - ---------------------- + ---------------- + ---------------------- + cos(x)
sin(x)             2                     3                   sin(x)                 
                sin (x)               sin (x)                                       
2(tan2(x)+1)tan(x)sin(x)2(tan2(x)+1)cos(x)sin2(x)+cos(x)+tan(x)sin(x)+2cos2(x)tan(x)sin3(x)\frac{2 \left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}}{\sin{\left(x \right)}} - \frac{2 \left(\tan^{2}{\left(x \right)} + 1\right) \cos{\left(x \right)}}{\sin^{2}{\left(x \right)}} + \cos{\left(x \right)} + \frac{\tan{\left(x \right)}}{\sin{\left(x \right)}} + \frac{2 \cos^{2}{\left(x \right)} \tan{\left(x \right)}}{\sin^{3}{\left(x \right)}}
The third derivative [src]
                         2                                                                                                                                           
            /       2   \      /       2   \        3                                    2    /       2   \        2    /       2   \     /       2   \              
          2*\1 + tan (x)/    3*\1 + tan (x)/   6*cos (x)*tan(x)   5*cos(x)*tan(x)   4*tan (x)*\1 + tan (x)/   6*cos (x)*\1 + tan (x)/   6*\1 + tan (x)/*cos(x)*tan(x)
-sin(x) + ---------------- + --------------- - ---------------- - --------------- + ----------------------- + ----------------------- - -----------------------------
               sin(x)             sin(x)              4                  2                   sin(x)                      3                            2              
                                                   sin (x)            sin (x)                                         sin (x)                      sin (x)           
2(tan2(x)+1)2sin(x)+4(tan2(x)+1)tan2(x)sin(x)+3(tan2(x)+1)sin(x)6(tan2(x)+1)cos(x)tan(x)sin2(x)+6(tan2(x)+1)cos2(x)sin3(x)sin(x)5cos(x)tan(x)sin2(x)6cos3(x)tan(x)sin4(x)\frac{2 \left(\tan^{2}{\left(x \right)} + 1\right)^{2}}{\sin{\left(x \right)}} + \frac{4 \left(\tan^{2}{\left(x \right)} + 1\right) \tan^{2}{\left(x \right)}}{\sin{\left(x \right)}} + \frac{3 \left(\tan^{2}{\left(x \right)} + 1\right)}{\sin{\left(x \right)}} - \frac{6 \left(\tan^{2}{\left(x \right)} + 1\right) \cos{\left(x \right)} \tan{\left(x \right)}}{\sin^{2}{\left(x \right)}} + \frac{6 \left(\tan^{2}{\left(x \right)} + 1\right) \cos^{2}{\left(x \right)}}{\sin^{3}{\left(x \right)}} - \sin{\left(x \right)} - \frac{5 \cos{\left(x \right)} \tan{\left(x \right)}}{\sin^{2}{\left(x \right)}} - \frac{6 \cos^{3}{\left(x \right)} \tan{\left(x \right)}}{\sin^{4}{\left(x \right)}}
The graph
Derivative of y=tgx/sinx-cosx