Mister Exam

Derivative of y=x×tg3x+2^x

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

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              x
x*tan(3*x) + 2 
2x+xtan(3x)2^{x} + x \tan{\left(3 x \right)}
x*tan(3*x) + 2^x
Detail solution
  1. Differentiate 2x+xtan(3x)2^{x} + x \tan{\left(3 x \right)} term by term:

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

      1. Apply the power rule: xx goes to 11

      g(x)=tan(3x)g{\left(x \right)} = \tan{\left(3 x \right)}; to find ddxg(x)\frac{d}{d x} g{\left(x \right)}:

      1. Rewrite the function to be differentiated:

        tan(3x)=sin(3x)cos(3x)\tan{\left(3 x \right)} = \frac{\sin{\left(3 x \right)}}{\cos{\left(3 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(3x)f{\left(x \right)} = \sin{\left(3 x \right)} and g(x)=cos(3x)g{\left(x \right)} = \cos{\left(3 x \right)}.

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

        1. Let u=3xu = 3 x.

        2. The derivative of sine is cosine:

          ddusin(u)=cos(u)\frac{d}{d u} \sin{\left(u \right)} = \cos{\left(u \right)}

        3. Then, apply the chain rule. Multiply by ddx3x\frac{d}{d x} 3 x:

          1. 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: 33

          The result of the chain rule is:

          3cos(3x)3 \cos{\left(3 x \right)}

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

        1. Let u=3xu = 3 x.

        2. The derivative of cosine is negative sine:

          dducos(u)=sin(u)\frac{d}{d u} \cos{\left(u \right)} = - \sin{\left(u \right)}

        3. Then, apply the chain rule. Multiply by ddx3x\frac{d}{d x} 3 x:

          1. 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: 33

          The result of the chain rule is:

          3sin(3x)- 3 \sin{\left(3 x \right)}

        Now plug in to the quotient rule:

        3sin2(3x)+3cos2(3x)cos2(3x)\frac{3 \sin^{2}{\left(3 x \right)} + 3 \cos^{2}{\left(3 x \right)}}{\cos^{2}{\left(3 x \right)}}

      The result is: x(3sin2(3x)+3cos2(3x))cos2(3x)+tan(3x)\frac{x \left(3 \sin^{2}{\left(3 x \right)} + 3 \cos^{2}{\left(3 x \right)}\right)}{\cos^{2}{\left(3 x \right)}} + \tan{\left(3 x \right)}

    2. ddx2x=2xlog(2)\frac{d}{d x} 2^{x} = 2^{x} \log{\left(2 \right)}

    The result is: 2xlog(2)+x(3sin2(3x)+3cos2(3x))cos2(3x)+tan(3x)2^{x} \log{\left(2 \right)} + \frac{x \left(3 \sin^{2}{\left(3 x \right)} + 3 \cos^{2}{\left(3 x \right)}\right)}{\cos^{2}{\left(3 x \right)}} + \tan{\left(3 x \right)}

  2. Now simplify:

    2xlog(2)+3xcos2(3x)+tan(3x)2^{x} \log{\left(2 \right)} + \frac{3 x}{\cos^{2}{\left(3 x \right)}} + \tan{\left(3 x \right)}


The answer is:

2xlog(2)+3xcos2(3x)+tan(3x)2^{x} \log{\left(2 \right)} + \frac{3 x}{\cos^{2}{\left(3 x \right)}} + \tan{\left(3 x \right)}

The graph
02468-8-6-4-2-1010-10000001000000
The first derivative [src]
  /         2     \    x                  
x*\3 + 3*tan (3*x)/ + 2 *log(2) + tan(3*x)
2xlog(2)+x(3tan2(3x)+3)+tan(3x)2^{x} \log{\left(2 \right)} + x \left(3 \tan^{2}{\left(3 x \right)} + 3\right) + \tan{\left(3 x \right)}
The second derivative [src]
         2         x    2           /       2     \         
6 + 6*tan (3*x) + 2 *log (2) + 18*x*\1 + tan (3*x)/*tan(3*x)
2xlog(2)2+18x(tan2(3x)+1)tan(3x)+6tan2(3x)+62^{x} \log{\left(2 \right)}^{2} + 18 x \left(\tan^{2}{\left(3 x \right)} + 1\right) \tan{\left(3 x \right)} + 6 \tan^{2}{\left(3 x \right)} + 6
The third derivative [src]
                                 2                                                                
 x    3           /       2     \       /       2     \                     2      /       2     \
2 *log (2) + 54*x*\1 + tan (3*x)/  + 54*\1 + tan (3*x)/*tan(3*x) + 108*x*tan (3*x)*\1 + tan (3*x)/
2xlog(2)3+54x(tan2(3x)+1)2+108x(tan2(3x)+1)tan2(3x)+54(tan2(3x)+1)tan(3x)2^{x} \log{\left(2 \right)}^{3} + 54 x \left(\tan^{2}{\left(3 x \right)} + 1\right)^{2} + 108 x \left(\tan^{2}{\left(3 x \right)} + 1\right) \tan^{2}{\left(3 x \right)} + 54 \left(\tan^{2}{\left(3 x \right)} + 1\right) \tan{\left(3 x \right)}
The graph
Derivative of y=x×tg3x+2^x