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sin^3x/cos^4x

Integral of sin^3x/cos^4x dx

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01sin3(x)cos4(x)dx\int\limits_{0}^{1} \frac{\sin^{3}{\left(x \right)}}{\cos^{4}{\left(x \right)}}\, dx
Detail solution
  1. Rewrite the integrand:

    sin3(x)cos4(x)=(1cos2(x))sin(x)cos4(x)\frac{\sin^{3}{\left(x \right)}}{\cos^{4}{\left(x \right)}} = \frac{\left(1 - \cos^{2}{\left(x \right)}\right) \sin{\left(x \right)}}{\cos^{4}{\left(x \right)}}

  2. There are multiple ways to do this integral.

    Method #1

    1. Let u=cos(x)u = \cos{\left(x \right)}.

      Then let du=sin(x)dxdu = - \sin{\left(x \right)} dx and substitute dudu:

      u21u4du\int \frac{u^{2} - 1}{u^{4}}\, du

      1. Rewrite the integrand:

        u21u4=1u21u4\frac{u^{2} - 1}{u^{4}} = \frac{1}{u^{2}} - \frac{1}{u^{4}}

      2. Integrate term-by-term:

        1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

          1u2du=1u\int \frac{1}{u^{2}}\, du = - \frac{1}{u}

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

          (1u4)du=1u4du\int \left(- \frac{1}{u^{4}}\right)\, du = - \int \frac{1}{u^{4}}\, du

          1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

            1u4du=13u3\int \frac{1}{u^{4}}\, du = - \frac{1}{3 u^{3}}

          So, the result is: 13u3\frac{1}{3 u^{3}}

        The result is: 1u+13u3- \frac{1}{u} + \frac{1}{3 u^{3}}

      Now substitute uu back in:

      1cos(x)+13cos3(x)- \frac{1}{\cos{\left(x \right)}} + \frac{1}{3 \cos^{3}{\left(x \right)}}

    Method #2

    1. Rewrite the integrand:

      (1cos2(x))sin(x)cos4(x)=sin(x)cos2(x)+sin(x)cos4(x)\frac{\left(1 - \cos^{2}{\left(x \right)}\right) \sin{\left(x \right)}}{\cos^{4}{\left(x \right)}} = \frac{- \sin{\left(x \right)} \cos^{2}{\left(x \right)} + \sin{\left(x \right)}}{\cos^{4}{\left(x \right)}}

    2. Let u=cos(x)u = \cos{\left(x \right)}.

      Then let du=sin(x)dxdu = - \sin{\left(x \right)} dx and substitute dudu:

      u21u4du\int \frac{u^{2} - 1}{u^{4}}\, du

      1. Rewrite the integrand:

        u21u4=1u21u4\frac{u^{2} - 1}{u^{4}} = \frac{1}{u^{2}} - \frac{1}{u^{4}}

      2. Integrate term-by-term:

        1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

          1u2du=1u\int \frac{1}{u^{2}}\, du = - \frac{1}{u}

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

          (1u4)du=1u4du\int \left(- \frac{1}{u^{4}}\right)\, du = - \int \frac{1}{u^{4}}\, du

          1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

            1u4du=13u3\int \frac{1}{u^{4}}\, du = - \frac{1}{3 u^{3}}

          So, the result is: 13u3\frac{1}{3 u^{3}}

        The result is: 1u+13u3- \frac{1}{u} + \frac{1}{3 u^{3}}

      Now substitute uu back in:

      1cos(x)+13cos3(x)- \frac{1}{\cos{\left(x \right)}} + \frac{1}{3 \cos^{3}{\left(x \right)}}

    Method #3

    1. Rewrite the integrand:

      (1cos2(x))sin(x)cos4(x)=sin(x)cos2(x)+sin(x)cos4(x)\frac{\left(1 - \cos^{2}{\left(x \right)}\right) \sin{\left(x \right)}}{\cos^{4}{\left(x \right)}} = - \frac{\sin{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \frac{\sin{\left(x \right)}}{\cos^{4}{\left(x \right)}}

    2. Integrate term-by-term:

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

        (sin(x)cos2(x))dx=sin(x)cos2(x)dx\int \left(- \frac{\sin{\left(x \right)}}{\cos^{2}{\left(x \right)}}\right)\, dx = - \int \frac{\sin{\left(x \right)}}{\cos^{2}{\left(x \right)}}\, dx

        1. Let u=cos(x)u = \cos{\left(x \right)}.

          Then let du=sin(x)dxdu = - \sin{\left(x \right)} dx and substitute du- du:

          1u2du\int \frac{1}{u^{2}}\, du

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

            (1u2)du=1u2du\int \left(- \frac{1}{u^{2}}\right)\, du = - \int \frac{1}{u^{2}}\, du

            1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

              1u2du=1u\int \frac{1}{u^{2}}\, du = - \frac{1}{u}

            So, the result is: 1u\frac{1}{u}

          Now substitute uu back in:

          1cos(x)\frac{1}{\cos{\left(x \right)}}

        So, the result is: 1cos(x)- \frac{1}{\cos{\left(x \right)}}

      1. Let u=cos(x)u = \cos{\left(x \right)}.

        Then let du=sin(x)dxdu = - \sin{\left(x \right)} dx and substitute du- du:

        1u4du\int \frac{1}{u^{4}}\, du

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

          (1u4)du=1u4du\int \left(- \frac{1}{u^{4}}\right)\, du = - \int \frac{1}{u^{4}}\, du

          1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

            1u4du=13u3\int \frac{1}{u^{4}}\, du = - \frac{1}{3 u^{3}}

          So, the result is: 13u3\frac{1}{3 u^{3}}

        Now substitute uu back in:

        13cos3(x)\frac{1}{3 \cos^{3}{\left(x \right)}}

      The result is: 1cos(x)+13cos3(x)- \frac{1}{\cos{\left(x \right)}} + \frac{1}{3 \cos^{3}{\left(x \right)}}

  3. Now simplify:

    3+1cos2(x)3cos(x)\frac{-3 + \frac{1}{\cos^{2}{\left(x \right)}}}{3 \cos{\left(x \right)}}

  4. Add the constant of integration:

    3+1cos2(x)3cos(x)+constant\frac{-3 + \frac{1}{\cos^{2}{\left(x \right)}}}{3 \cos{\left(x \right)}}+ \mathrm{constant}


The answer is:

3+1cos2(x)3cos(x)+constant\frac{-3 + \frac{1}{\cos^{2}{\left(x \right)}}}{3 \cos{\left(x \right)}}+ \mathrm{constant}

The answer (Indefinite) [src]
  /                                   
 |                                    
 |    3                               
 | sin (x)            1          1    
 | ------- dx = C - ------ + ---------
 |    4             cos(x)        3   
 | cos (x)                   3*cos (x)
 |                                    
/                                     
3cos2x13cos3x-{{3\,\cos ^2x-1}\over{3\,\cos ^3x}}
The graph
0.001.000.100.200.300.400.500.600.700.800.90-1010
The answer [src]
             2   
2   1 - 3*cos (1)
- + -------------
3          3     
      3*cos (1)  
1cos1+13cos31+23-{{1}\over{\cos 1}}+{{1}\over{3\,\cos ^31}}+{{2}\over{3}}
=
=
             2   
2   1 - 3*cos (1)
- + -------------
3          3     
      3*cos (1)  
3cos2(1)+13cos3(1)+23\frac{- 3 \cos^{2}{\left(1 \right)} + 1}{3 \cos^{3}{\left(1 \right)}} + \frac{2}{3}
Numerical answer [src]
0.92918564057767
0.92918564057767
The graph
Integral of sin^3x/cos^4x dx

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