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Integral of sin(7x)*(x*cos(2x))*dx dx

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The solution

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 |  sin(7*x)*x*cos(2*x) dx
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$$\int\limits_{0}^{1} x \cos{\left(2 x \right)} \sin{\left(7 x \right)}\, dx$$
Integral(sin(7*x)*(x*cos(2*x)), (x, 0, 1))
Detail solution
  1. Use integration by parts:

    Let and let .

    Then .

    To find :

    1. Rewrite the integrand:

    2. Integrate term-by-term:

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

        1. Rewrite the integrand:

        2. There are multiple ways to do this integral.

          Method #1

          1. Let .

            Then let and substitute :

            1. Integrate term-by-term:

              1. The integral of is when :

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

                1. The integral of is when :

                So, the result is:

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

                1. The integral of is when :

                So, the result is:

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

                1. The integral of is when :

                So, the result is:

              The result is:

            Now substitute back in:

          Method #2

          1. Rewrite the integrand:

          2. Integrate term-by-term:

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

              1. Let .

                Then let and substitute :

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

                  1. The integral of is when :

                  So, the result is:

                Now substitute back in:

              So, the result is:

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

              1. Let .

                Then let and substitute :

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

                  1. The integral of is when :

                  So, the result is:

                Now substitute back in:

              So, the result is:

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

              1. Let .

                Then let and substitute :

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

                  1. The integral of is when :

                  So, the result is:

                Now substitute back in:

              So, the result is:

            1. Let .

              Then let and substitute :

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

                1. The integral of is when :

                So, the result is:

              Now substitute back in:

            The result is:

          Method #3

          1. Rewrite the integrand:

          2. Integrate term-by-term:

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

              1. Let .

                Then let and substitute :

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

                  1. The integral of is when :

                  So, the result is:

                Now substitute back in:

              So, the result is:

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

              1. Let .

                Then let and substitute :

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

                  1. The integral of is when :

                  So, the result is:

                Now substitute back in:

              So, the result is:

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

              1. Let .

                Then let and substitute :

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

                  1. The integral of is when :

                  So, the result is:

                Now substitute back in:

              So, the result is:

            1. Let .

              Then let and substitute :

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

                1. The integral of is when :

                So, the result is:

              Now substitute back in:

            The result is:

        So, the result is:

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

        1. Rewrite the integrand:

        2. Rewrite the integrand:

        3. Integrate term-by-term:

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

            1. Let .

              Then let and substitute :

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

                1. The integral of is when :

                So, the result is:

              Now substitute back in:

            So, the result is:

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

            1. Let .

              Then let and substitute :

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

                1. The integral of is when :

                So, the result is:

              Now substitute back in:

            So, the result is:

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

            1. Let .

              Then let and substitute :

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

                1. The integral of is when :

                So, the result is:

              Now substitute back in:

            So, the result is:

          1. The integral of sine is negative cosine:

          The result is:

        So, the result is:

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

        1. Rewrite the integrand:

        2. Let .

          Then let and substitute :

          1. Integrate term-by-term:

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

              1. The integral of is when :

              So, the result is:

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

              1. The integral of is when :

              So, the result is:

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

              1. The integral of is when :

              So, the result is:

            The result is:

          Now substitute back in:

        So, the result is:

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

        1. Rewrite the integrand:

        2. Rewrite the integrand:

        3. Integrate term-by-term:

          1. Let .

            Then let and substitute :

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

              1. The integral of is when :

              So, the result is:

            Now substitute back in:

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

            1. Let .

              Then let and substitute :

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

                1. The integral of is when :

                So, the result is:

              Now substitute back in:

            So, the result is:

          1. The integral of sine is negative cosine:

          The result is:

        So, the result is:

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

        1. Rewrite the integrand:

        2. Let .

          Then let and substitute :

          1. Integrate term-by-term:

            1. The integral of is when :

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

              1. The integral of is when :

              So, the result is:

            The result is:

          Now substitute back in:

        So, the result is:

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

        1. Rewrite the integrand:

        2. Let .

          Then let and substitute :

          1. Integrate term-by-term:

            1. The integral of is when :

            1. The integral of a constant is the constant times the variable of integration:

            The result is:

          Now substitute back in:

        So, the result is:

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

        1. Let .

          Then let and substitute :

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

            1. The integral of is when :

            So, the result is:

          Now substitute back in:

        So, the result is:

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

        1. The integral of sine is negative cosine:

        So, the result is:

      The result is:

    Now evaluate the sub-integral.

  2. Integrate term-by-term:

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

      1. Rewrite the integrand:

      2. Rewrite the integrand:

      3. Integrate term-by-term:

        1. Let .

          Then let and substitute :

          1. The integral of is when :

          Now substitute back in:

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

          1. Let .

            Then let and substitute :

            1. The integral of is when :

            Now substitute back in:

          So, the result is:

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

          1. Let .

            Then let and substitute :

            1. The integral of is when :

            Now substitute back in:

          So, the result is:

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

          1. Let .

            Then let and substitute :

            1. The integral of is when :

            Now substitute back in:

          So, the result is:

        1. The integral of cosine is sine:

        The result is:

      So, the result is:

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

      1. Rewrite the integrand:

      2. Rewrite the integrand:

      3. Integrate term-by-term:

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

          1. Let .

            Then let and substitute :

            1. The integral of is when :

            Now substitute back in:

          So, the result is:

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

          1. Let .

            Then let and substitute :

            1. The integral of is when :

            Now substitute back in:

          So, the result is:

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

          1. Let .

            Then let and substitute :

            1. The integral of is when :

            Now substitute back in:

          So, the result is:

        1. The integral of cosine is sine:

        The result is:

      So, the result is:

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

      1. Rewrite the integrand:

      2. Rewrite the integrand:

      3. Integrate term-by-term:

        1. Let .

          Then let and substitute :

          1. The integral of is when :

          Now substitute back in:

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

          1. Let .

            Then let and substitute :

            1. The integral of is when :

            Now substitute back in:

          So, the result is:

        1. The integral of cosine is sine:

        The result is:

      So, the result is:

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

      1. Rewrite the integrand:

      2. Let .

        Then let and substitute :

        1. Integrate term-by-term:

          1. The integral of a constant is the constant times the variable of integration:

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

            1. The integral of is when :

            So, the result is:

          The result is:

        Now substitute back in:

      So, the result is:

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

      1. The integral of cosine is sine:

      So, the result is:

    The result is:

  3. Now simplify:

  4. Add the constant of integration:


The answer is:

The answer (Indefinite) [src]
  /                                    3            7                        9             5        /                              5             9            3   \
 |                              154*sin (x)   32*sin (x)   7*sin(x)   128*sin (x)   224*sin (x)     |                7      128*cos (x)   128*cos (x)   26*cos (x)|
 | sin(7*x)*x*cos(2*x) dx = C - ----------- - ---------- + -------- + ----------- + ----------- + x*|-cos(x) + 32*cos (x) - ----------- - ----------- + ----------|
 |                                  135           9           45           81            75         \                            5             9            3     /
/                                                                                                                                                                  
$$\int x \cos{\left(2 x \right)} \sin{\left(7 x \right)}\, dx = C + x \left(- \frac{128 \cos^{9}{\left(x \right)}}{9} + 32 \cos^{7}{\left(x \right)} - \frac{128 \cos^{5}{\left(x \right)}}{5} + \frac{26 \cos^{3}{\left(x \right)}}{3} - \cos{\left(x \right)}\right) + \frac{128 \sin^{9}{\left(x \right)}}{81} - \frac{32 \sin^{7}{\left(x \right)}}{9} + \frac{224 \sin^{5}{\left(x \right)}}{75} - \frac{154 \sin^{3}{\left(x \right)}}{135} + \frac{7 \sin{\left(x \right)}}{45}$$
The graph
The answer [src]
  28*cos(7)*sin(2)   7*cos(2)*cos(7)   2*sin(2)*sin(7)   53*cos(2)*sin(7)
- ---------------- - --------------- - --------------- + ----------------
        2025                45                45               2025      
$$- \frac{2 \sin{\left(2 \right)} \sin{\left(7 \right)}}{45} - \frac{28 \sin{\left(2 \right)} \cos{\left(7 \right)}}{2025} + \frac{53 \sin{\left(7 \right)} \cos{\left(2 \right)}}{2025} - \frac{7 \cos{\left(2 \right)} \cos{\left(7 \right)}}{45}$$
=
=
  28*cos(7)*sin(2)   7*cos(2)*cos(7)   2*sin(2)*sin(7)   53*cos(2)*sin(7)
- ---------------- - --------------- - --------------- + ----------------
        2025                45                45               2025      
$$- \frac{2 \sin{\left(2 \right)} \sin{\left(7 \right)}}{45} - \frac{28 \sin{\left(2 \right)} \cos{\left(7 \right)}}{2025} + \frac{53 \sin{\left(7 \right)} \cos{\left(2 \right)}}{2025} - \frac{7 \cos{\left(2 \right)} \cos{\left(7 \right)}}{45}$$
-28*cos(7)*sin(2)/2025 - 7*cos(2)*cos(7)/45 - 2*sin(2)*sin(7)/45 + 53*cos(2)*sin(7)/2025
Numerical answer [src]
0.00561758510982108
0.00561758510982108

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