Mister Exam

Derivative of z*cosz

Function f() - derivative -N order at the point
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The graph:

from to

Piecewise:

The solution

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

    ddzf(z)g(z)=f(z)ddzg(z)+g(z)ddzf(z)\frac{d}{d z} f{\left(z \right)} g{\left(z \right)} = f{\left(z \right)} \frac{d}{d z} g{\left(z \right)} + g{\left(z \right)} \frac{d}{d z} f{\left(z \right)}

    f(z)=zf{\left(z \right)} = z; to find ddzf(z)\frac{d}{d z} f{\left(z \right)}:

    1. Apply the power rule: zz goes to 11

    g(z)=cos(z)g{\left(z \right)} = \cos{\left(z \right)}; to find ddzg(z)\frac{d}{d z} g{\left(z \right)}:

    1. The derivative of cosine is negative sine:

      ddzcos(z)=sin(z)\frac{d}{d z} \cos{\left(z \right)} = - \sin{\left(z \right)}

    The result is: zsin(z)+cos(z)- z \sin{\left(z \right)} + \cos{\left(z \right)}


The answer is:

zsin(z)+cos(z)- z \sin{\left(z \right)} + \cos{\left(z \right)}

The graph
02468-8-6-4-2-1010-2020
The first derivative [src]
-z*sin(z) + cos(z)
zsin(z)+cos(z)- z \sin{\left(z \right)} + \cos{\left(z \right)}
The second derivative [src]
-(2*sin(z) + z*cos(z))
(zcos(z)+2sin(z))- (z \cos{\left(z \right)} + 2 \sin{\left(z \right)})
The third derivative [src]
-3*cos(z) + z*sin(z)
zsin(z)3cos(z)z \sin{\left(z \right)} - 3 \cos{\left(z \right)}
The graph
Derivative of z*cosz