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(x+2)^2*cos(3x)

Integral of (x+2)^2*cos(3x) dx

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20(x+2)2cos(3x)dx\int\limits_{-2}^{0} \left(x + 2\right)^{2} \cos{\left(3 x \right)}\, dx
Integral((x + 2)^2*cos(3*x), (x, -2, 0))
Detail solution
  1. There are multiple ways to do this integral.

    Method #1

    1. Rewrite the integrand:

      (x+2)2cos(3x)=x2cos(3x)+4xcos(3x)+4cos(3x)\left(x + 2\right)^{2} \cos{\left(3 x \right)} = x^{2} \cos{\left(3 x \right)} + 4 x \cos{\left(3 x \right)} + 4 \cos{\left(3 x \right)}

    2. Integrate term-by-term:

      1. Use integration by parts:

        udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

        Let u(x)=x2u{\left(x \right)} = x^{2} and let dv(x)=cos(3x)\operatorname{dv}{\left(x \right)} = \cos{\left(3 x \right)}.

        Then du(x)=2x\operatorname{du}{\left(x \right)} = 2 x.

        To find v(x)v{\left(x \right)}:

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

            1. The integral of cosine is sine:

              cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

            So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

          Now substitute uu back in:

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

        Now evaluate the sub-integral.

      2. Use integration by parts:

        udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

        Let u(x)=2x3u{\left(x \right)} = \frac{2 x}{3} and let dv(x)=sin(3x)\operatorname{dv}{\left(x \right)} = \sin{\left(3 x \right)}.

        Then du(x)=23\operatorname{du}{\left(x \right)} = \frac{2}{3}.

        To find v(x)v{\left(x \right)}:

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          sin(u)9du\int \frac{\sin{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            sin(u)3du=sin(u)du3\int \frac{\sin{\left(u \right)}}{3}\, du = \frac{\int \sin{\left(u \right)}\, du}{3}

            1. The integral of sine is negative cosine:

              sin(u)du=cos(u)\int \sin{\left(u \right)}\, du = - \cos{\left(u \right)}

            So, the result is: cos(u)3- \frac{\cos{\left(u \right)}}{3}

          Now substitute uu back in:

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

        Now evaluate the sub-integral.

      3. The integral of a constant times a function is the constant times the integral of the function:

        (2cos(3x)9)dx=2cos(3x)dx9\int \left(- \frac{2 \cos{\left(3 x \right)}}{9}\right)\, dx = - \frac{2 \int \cos{\left(3 x \right)}\, dx}{9}

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

            1. The integral of cosine is sine:

              cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

            So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

          Now substitute uu back in:

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

        So, the result is: 2sin(3x)27- \frac{2 \sin{\left(3 x \right)}}{27}

      1. The integral of a constant times a function is the constant times the integral of the function:

        4xcos(3x)dx=4xcos(3x)dx\int 4 x \cos{\left(3 x \right)}\, dx = 4 \int x \cos{\left(3 x \right)}\, dx

        1. Use integration by parts:

          udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

          Let u(x)=xu{\left(x \right)} = x and let dv(x)=cos(3x)\operatorname{dv}{\left(x \right)} = \cos{\left(3 x \right)}.

          Then du(x)=1\operatorname{du}{\left(x \right)} = 1.

          To find v(x)v{\left(x \right)}:

          1. Let u=3xu = 3 x.

            Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

            cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

            1. The integral of a constant times a function is the constant times the integral of the function:

              cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

              1. The integral of cosine is sine:

                cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

              So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

            Now substitute uu back in:

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

          Now evaluate the sub-integral.

        2. The integral of a constant times a function is the constant times the integral of the function:

          sin(3x)3dx=sin(3x)dx3\int \frac{\sin{\left(3 x \right)}}{3}\, dx = \frac{\int \sin{\left(3 x \right)}\, dx}{3}

          1. Let u=3xu = 3 x.

            Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

            sin(u)9du\int \frac{\sin{\left(u \right)}}{9}\, du

            1. The integral of a constant times a function is the constant times the integral of the function:

              sin(u)3du=sin(u)du3\int \frac{\sin{\left(u \right)}}{3}\, du = \frac{\int \sin{\left(u \right)}\, du}{3}

              1. The integral of sine is negative cosine:

                sin(u)du=cos(u)\int \sin{\left(u \right)}\, du = - \cos{\left(u \right)}

              So, the result is: cos(u)3- \frac{\cos{\left(u \right)}}{3}

            Now substitute uu back in:

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

          So, the result is: cos(3x)9- \frac{\cos{\left(3 x \right)}}{9}

        So, the result is: 4xsin(3x)3+4cos(3x)9\frac{4 x \sin{\left(3 x \right)}}{3} + \frac{4 \cos{\left(3 x \right)}}{9}

      1. The integral of a constant times a function is the constant times the integral of the function:

        4cos(3x)dx=4cos(3x)dx\int 4 \cos{\left(3 x \right)}\, dx = 4 \int \cos{\left(3 x \right)}\, dx

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

            1. The integral of cosine is sine:

              cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

            So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

          Now substitute uu back in:

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

        So, the result is: 4sin(3x)3\frac{4 \sin{\left(3 x \right)}}{3}

      The result is: x2sin(3x)3+4xsin(3x)3+2xcos(3x)9+34sin(3x)27+4cos(3x)9\frac{x^{2} \sin{\left(3 x \right)}}{3} + \frac{4 x \sin{\left(3 x \right)}}{3} + \frac{2 x \cos{\left(3 x \right)}}{9} + \frac{34 \sin{\left(3 x \right)}}{27} + \frac{4 \cos{\left(3 x \right)}}{9}

    Method #2

    1. Use integration by parts:

      udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

      Let u(x)=x2+4x+4u{\left(x \right)} = x^{2} + 4 x + 4 and let dv(x)=cos(3x)\operatorname{dv}{\left(x \right)} = \cos{\left(3 x \right)}.

      Then du(x)=2x+4\operatorname{du}{\left(x \right)} = 2 x + 4.

      To find v(x)v{\left(x \right)}:

      1. Let u=3xu = 3 x.

        Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

        cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

        1. The integral of a constant times a function is the constant times the integral of the function:

          cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

          1. The integral of cosine is sine:

            cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

          So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

        Now substitute uu back in:

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

      Now evaluate the sub-integral.

    2. Use integration by parts:

      udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

      Let u(x)=2x3+43u{\left(x \right)} = \frac{2 x}{3} + \frac{4}{3} and let dv(x)=sin(3x)\operatorname{dv}{\left(x \right)} = \sin{\left(3 x \right)}.

      Then du(x)=23\operatorname{du}{\left(x \right)} = \frac{2}{3}.

      To find v(x)v{\left(x \right)}:

      1. Let u=3xu = 3 x.

        Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

        sin(u)9du\int \frac{\sin{\left(u \right)}}{9}\, du

        1. The integral of a constant times a function is the constant times the integral of the function:

          sin(u)3du=sin(u)du3\int \frac{\sin{\left(u \right)}}{3}\, du = \frac{\int \sin{\left(u \right)}\, du}{3}

          1. The integral of sine is negative cosine:

            sin(u)du=cos(u)\int \sin{\left(u \right)}\, du = - \cos{\left(u \right)}

          So, the result is: cos(u)3- \frac{\cos{\left(u \right)}}{3}

        Now substitute uu back in:

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

      Now evaluate the sub-integral.

    3. The integral of a constant times a function is the constant times the integral of the function:

      (2cos(3x)9)dx=2cos(3x)dx9\int \left(- \frac{2 \cos{\left(3 x \right)}}{9}\right)\, dx = - \frac{2 \int \cos{\left(3 x \right)}\, dx}{9}

      1. Let u=3xu = 3 x.

        Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

        cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

        1. The integral of a constant times a function is the constant times the integral of the function:

          cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

          1. The integral of cosine is sine:

            cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

          So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

        Now substitute uu back in:

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

      So, the result is: 2sin(3x)27- \frac{2 \sin{\left(3 x \right)}}{27}

    Method #3

    1. Rewrite the integrand:

      (x+2)2cos(3x)=x2cos(3x)+4xcos(3x)+4cos(3x)\left(x + 2\right)^{2} \cos{\left(3 x \right)} = x^{2} \cos{\left(3 x \right)} + 4 x \cos{\left(3 x \right)} + 4 \cos{\left(3 x \right)}

    2. Integrate term-by-term:

      1. Use integration by parts:

        udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

        Let u(x)=x2u{\left(x \right)} = x^{2} and let dv(x)=cos(3x)\operatorname{dv}{\left(x \right)} = \cos{\left(3 x \right)}.

        Then du(x)=2x\operatorname{du}{\left(x \right)} = 2 x.

        To find v(x)v{\left(x \right)}:

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

            1. The integral of cosine is sine:

              cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

            So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

          Now substitute uu back in:

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

        Now evaluate the sub-integral.

      2. Use integration by parts:

        udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

        Let u(x)=2x3u{\left(x \right)} = \frac{2 x}{3} and let dv(x)=sin(3x)\operatorname{dv}{\left(x \right)} = \sin{\left(3 x \right)}.

        Then du(x)=23\operatorname{du}{\left(x \right)} = \frac{2}{3}.

        To find v(x)v{\left(x \right)}:

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          sin(u)9du\int \frac{\sin{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            sin(u)3du=sin(u)du3\int \frac{\sin{\left(u \right)}}{3}\, du = \frac{\int \sin{\left(u \right)}\, du}{3}

            1. The integral of sine is negative cosine:

              sin(u)du=cos(u)\int \sin{\left(u \right)}\, du = - \cos{\left(u \right)}

            So, the result is: cos(u)3- \frac{\cos{\left(u \right)}}{3}

          Now substitute uu back in:

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

        Now evaluate the sub-integral.

      3. The integral of a constant times a function is the constant times the integral of the function:

        (2cos(3x)9)dx=2cos(3x)dx9\int \left(- \frac{2 \cos{\left(3 x \right)}}{9}\right)\, dx = - \frac{2 \int \cos{\left(3 x \right)}\, dx}{9}

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

            1. The integral of cosine is sine:

              cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

            So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

          Now substitute uu back in:

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

        So, the result is: 2sin(3x)27- \frac{2 \sin{\left(3 x \right)}}{27}

      1. The integral of a constant times a function is the constant times the integral of the function:

        4xcos(3x)dx=4xcos(3x)dx\int 4 x \cos{\left(3 x \right)}\, dx = 4 \int x \cos{\left(3 x \right)}\, dx

        1. Use integration by parts:

          udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

          Let u(x)=xu{\left(x \right)} = x and let dv(x)=cos(3x)\operatorname{dv}{\left(x \right)} = \cos{\left(3 x \right)}.

          Then du(x)=1\operatorname{du}{\left(x \right)} = 1.

          To find v(x)v{\left(x \right)}:

          1. Let u=3xu = 3 x.

            Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

            cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

            1. The integral of a constant times a function is the constant times the integral of the function:

              cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

              1. The integral of cosine is sine:

                cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

              So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

            Now substitute uu back in:

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

          Now evaluate the sub-integral.

        2. The integral of a constant times a function is the constant times the integral of the function:

          sin(3x)3dx=sin(3x)dx3\int \frac{\sin{\left(3 x \right)}}{3}\, dx = \frac{\int \sin{\left(3 x \right)}\, dx}{3}

          1. Let u=3xu = 3 x.

            Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

            sin(u)9du\int \frac{\sin{\left(u \right)}}{9}\, du

            1. The integral of a constant times a function is the constant times the integral of the function:

              sin(u)3du=sin(u)du3\int \frac{\sin{\left(u \right)}}{3}\, du = \frac{\int \sin{\left(u \right)}\, du}{3}

              1. The integral of sine is negative cosine:

                sin(u)du=cos(u)\int \sin{\left(u \right)}\, du = - \cos{\left(u \right)}

              So, the result is: cos(u)3- \frac{\cos{\left(u \right)}}{3}

            Now substitute uu back in:

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

          So, the result is: cos(3x)9- \frac{\cos{\left(3 x \right)}}{9}

        So, the result is: 4xsin(3x)3+4cos(3x)9\frac{4 x \sin{\left(3 x \right)}}{3} + \frac{4 \cos{\left(3 x \right)}}{9}

      1. The integral of a constant times a function is the constant times the integral of the function:

        4cos(3x)dx=4cos(3x)dx\int 4 \cos{\left(3 x \right)}\, dx = 4 \int \cos{\left(3 x \right)}\, dx

        1. Let u=3xu = 3 x.

          Then let du=3dxdu = 3 dx and substitute du3\frac{du}{3}:

          cos(u)9du\int \frac{\cos{\left(u \right)}}{9}\, du

          1. The integral of a constant times a function is the constant times the integral of the function:

            cos(u)3du=cos(u)du3\int \frac{\cos{\left(u \right)}}{3}\, du = \frac{\int \cos{\left(u \right)}\, du}{3}

            1. The integral of cosine is sine:

              cos(u)du=sin(u)\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}

            So, the result is: sin(u)3\frac{\sin{\left(u \right)}}{3}

          Now substitute uu back in:

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

        So, the result is: 4sin(3x)3\frac{4 \sin{\left(3 x \right)}}{3}

      The result is: x2sin(3x)3+4xsin(3x)3+2xcos(3x)9+34sin(3x)27+4cos(3x)9\frac{x^{2} \sin{\left(3 x \right)}}{3} + \frac{4 x \sin{\left(3 x \right)}}{3} + \frac{2 x \cos{\left(3 x \right)}}{9} + \frac{34 \sin{\left(3 x \right)}}{27} + \frac{4 \cos{\left(3 x \right)}}{9}

  2. Add the constant of integration:

    x2sin(3x)3+4xsin(3x)3+2xcos(3x)9+34sin(3x)27+4cos(3x)9+constant\frac{x^{2} \sin{\left(3 x \right)}}{3} + \frac{4 x \sin{\left(3 x \right)}}{3} + \frac{2 x \cos{\left(3 x \right)}}{9} + \frac{34 \sin{\left(3 x \right)}}{27} + \frac{4 \cos{\left(3 x \right)}}{9}+ \mathrm{constant}


The answer is:

x2sin(3x)3+4xsin(3x)3+2xcos(3x)9+34sin(3x)27+4cos(3x)9+constant\frac{x^{2} \sin{\left(3 x \right)}}{3} + \frac{4 x \sin{\left(3 x \right)}}{3} + \frac{2 x \cos{\left(3 x \right)}}{9} + \frac{34 \sin{\left(3 x \right)}}{27} + \frac{4 \cos{\left(3 x \right)}}{9}+ \mathrm{constant}

The answer (Indefinite) [src]
  /                                                                                               
 |                                                        2                                       
 |        2                   4*cos(3*x)   34*sin(3*x)   x *sin(3*x)   2*x*cos(3*x)   4*x*sin(3*x)
 | (x + 2) *cos(3*x) dx = C + ---------- + ----------- + ----------- + ------------ + ------------
 |                                9             27            3             9              3      
/                                                                                                 
(9x22)sin(3x)+6xcos(3x)9+4(3xsin(3x)+cos(3x))3+4sin(3x)3{{{{\left(9\,x^2-2\right)\,\sin \left(3\,x\right)+6\,x\,\cos \left( 3\,x\right)}\over{9}}+{{4\,\left(3\,x\,\sin \left(3\,x\right)+\cos \left(3\,x\right)\right)}\over{3}}+4\,\sin \left(3\,x\right)}\over{3 }}
The graph
-2.0-1.8-1.6-1.4-1.2-1.0-0.8-0.6-0.4-0.20.05-5
The answer [src]
4   2*sin(6)
- - --------
9      27   
492sin627{{4}\over{9}}-{{2\,\sin 6}\over{27}}
=
=
4   2*sin(6)
- - --------
9      27   
2sin(6)27+49- \frac{2 \sin{\left(6 \right)}}{27} + \frac{4}{9}
Numerical answer [src]
0.465141888755476
0.465141888755476
The graph
Integral of (x+2)^2*cos(3x) dx

    Use the examples entering the upper and lower limits of integration.