Mister Exam

Derivative of (0,5-x)cosx+sinx

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

from to

Piecewise:

The solution

You have entered [src]
(1/2 - x)*cos(x) + sin(x)
(12x)cos(x)+sin(x)\left(\frac{1}{2} - x\right) \cos{\left(x \right)} + \sin{\left(x \right)}
(1/2 - x)*cos(x) + sin(x)
Detail solution
  1. Differentiate (12x)cos(x)+sin(x)\left(\frac{1}{2} - x\right) \cos{\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)=(12x)cos(x)f{\left(x \right)} = \left(1 - 2 x\right) \cos{\left(x \right)} and g(x)=2g{\left(x \right)} = 2.

      To find ddxf(x)\frac{d}{d x} f{\left(x \right)}:

      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)=12xf{\left(x \right)} = 1 - 2 x; to find ddxf(x)\frac{d}{d x} f{\left(x \right)}:

        1. Differentiate 12x1 - 2 x term by term:

          1. The derivative of the constant 11 is zero.

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

            1. Apply the power rule: xx goes to 11

            So, the result is: 2-2

          The result is: 2-2

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

        The result is: (12x)sin(x)2cos(x)- \left(1 - 2 x\right) \sin{\left(x \right)} - 2 \cos{\left(x \right)}

      To find ddxg(x)\frac{d}{d x} g{\left(x \right)}:

      1. The derivative of the constant 22 is zero.

      Now plug in to the quotient rule:

      (12x)sin(x)2cos(x)- \frac{\left(1 - 2 x\right) \sin{\left(x \right)}}{2} - \cos{\left(x \right)}

    2. 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: (12x)sin(x)2- \frac{\left(1 - 2 x\right) \sin{\left(x \right)}}{2}

  2. Now simplify:

    (x12)sin(x)\left(x - \frac{1}{2}\right) \sin{\left(x \right)}


The answer is:

(x12)sin(x)\left(x - \frac{1}{2}\right) \sin{\left(x \right)}

The graph
02468-8-6-4-2-1010-2020
The first derivative [src]
-(1/2 - x)*sin(x)
(12x)sin(x)- \left(\frac{1}{2} - x\right) \sin{\left(x \right)}
The second derivative [src]
(-1 + 2*x)*cos(x)         
----------------- + sin(x)
        2                 
(2x1)cos(x)2+sin(x)\frac{\left(2 x - 1\right) \cos{\left(x \right)}}{2} + \sin{\left(x \right)}
The third derivative [src]
           (-1 + 2*x)*sin(x)
2*cos(x) - -----------------
                   2        
(2x1)sin(x)2+2cos(x)- \frac{\left(2 x - 1\right) \sin{\left(x \right)}}{2} + 2 \cos{\left(x \right)}
The graph
Derivative of (0,5-x)cosx+sinx