Mister Exam

Derivative of cos(x)*sin(x)

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

The graph:

from to

Piecewise:

The solution

You have entered [src]
cos(x)*sin(x)
sin(x)cos(x)\sin{\left(x \right)} \cos{\left(x \right)}
cos(x)*sin(x)
Detail solution
  1. Apply the product rule:

    ddxf(x)g(x)=f(x)ddxg(x)+g(x)ddxf(x)\frac{d}{d x} f{\left(x \right)} g{\left(x \right)} = f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}

    f(x)=cos(x)f{\left(x \right)} = \cos{\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)}

    g(x)=sin(x)g{\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)}

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

  2. Now simplify:

    cos(2x)\cos{\left(2 x \right)}


The answer is:

cos(2x)\cos{\left(2 x \right)}

The graph
02468-8-6-4-2-10102-2
The first derivative [src]
   2         2   
cos (x) - sin (x)
sin2(x)+cos2(x)- \sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}
The second derivative [src]
-4*cos(x)*sin(x)
4sin(x)cos(x)- 4 \sin{\left(x \right)} \cos{\left(x \right)}
The third derivative [src]
  /   2         2   \
4*\sin (x) - cos (x)/
4(sin2(x)cos2(x))4 \left(\sin^{2}{\left(x \right)} - \cos^{2}{\left(x \right)}\right)
The graph
Derivative of cos(x)*sin(x)