Sr Examen

Integral de x²cos(x²) dx

Límites de integración:

interior superior
v

Gráfico:

interior superior

Definida a trozos:

Solución

Ha introducido [src]
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 |   2    / 2\   
 |  x *cos\x / dx
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0                
01x2cos(x2)dx\int\limits_{0}^{1} x^{2} \cos{\left(x^{2} \right)}\, dx
Integral(x^2*cos(x^2), (x, 0, 1))
Solución detallada
  1. Usamos la integración por partes:

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

    que u(x)=x2u{\left(x \right)} = x^{2} y que dv(x)=cos(x2)\operatorname{dv}{\left(x \right)} = \cos{\left(x^{2} \right)}.

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

    Para buscar v(x)v{\left(x \right)}:

      FresnelCRule(a=1, b=0, c=0, context=cos(x**2), symbol=x)

    Ahora resolvemos podintegral.

  2. La integral del producto de una función por una constante es la constante por la integral de esta función:

    2πxC(2xπ)dx=2πxC(2xπ)dx\int \sqrt{2} \sqrt{\pi} x C\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)\, dx = \sqrt{2} \sqrt{\pi} \int x C\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)\, dx

    1. No puedo encontrar los pasos en la búsqueda de esta integral.

      Pero la integral

      2x3Γ(14)Γ(34)2F3(14,3412,54,74|x44)16πΓ(54)Γ(74)\frac{\sqrt{2} x^{3} \Gamma\left(\frac{1}{4}\right) \Gamma\left(\frac{3}{4}\right) {{}_{2}F_{3}\left(\begin{matrix} \frac{1}{4}, \frac{3}{4} \\ \frac{1}{2}, \frac{5}{4}, \frac{7}{4} \end{matrix}\middle| {- \frac{x^{4}}{4}} \right)}}{16 \sqrt{\pi} \Gamma\left(\frac{5}{4}\right) \Gamma\left(\frac{7}{4}\right)}

    Por lo tanto, el resultado es: x3Γ(14)Γ(34)2F3(14,3412,54,74|x44)8Γ(54)Γ(74)\frac{x^{3} \Gamma\left(\frac{1}{4}\right) \Gamma\left(\frac{3}{4}\right) {{}_{2}F_{3}\left(\begin{matrix} \frac{1}{4}, \frac{3}{4} \\ \frac{1}{2}, \frac{5}{4}, \frac{7}{4} \end{matrix}\middle| {- \frac{x^{4}}{4}} \right)}}{8 \Gamma\left(\frac{5}{4}\right) \Gamma\left(\frac{7}{4}\right)}

  3. Ahora simplificar:

    x2(2x2F3(14,3412,54,74|x44)3+2πC(2xπ)2)x^{2} \left(- \frac{2 x {{}_{2}F_{3}\left(\begin{matrix} \frac{1}{4}, \frac{3}{4} \\ \frac{1}{2}, \frac{5}{4}, \frac{7}{4} \end{matrix}\middle| {- \frac{x^{4}}{4}} \right)}}{3} + \frac{\sqrt{2} \sqrt{\pi} C\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2}\right)

  4. Añadimos la constante de integración:

    x2(2x2F3(14,3412,54,74|x44)3+2πC(2xπ)2)+constantx^{2} \left(- \frac{2 x {{}_{2}F_{3}\left(\begin{matrix} \frac{1}{4}, \frac{3}{4} \\ \frac{1}{2}, \frac{5}{4}, \frac{7}{4} \end{matrix}\middle| {- \frac{x^{4}}{4}} \right)}}{3} + \frac{\sqrt{2} \sqrt{\pi} C\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2}\right)+ \mathrm{constant}


Respuesta:

x2(2x2F3(14,3412,54,74|x44)3+2πC(2xπ)2)+constantx^{2} \left(- \frac{2 x {{}_{2}F_{3}\left(\begin{matrix} \frac{1}{4}, \frac{3}{4} \\ \frac{1}{2}, \frac{5}{4}, \frac{7}{4} \end{matrix}\middle| {- \frac{x^{4}}{4}} \right)}}{3} + \frac{\sqrt{2} \sqrt{\pi} C\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2}\right)+ \mathrm{constant}

Respuesta (Indefinida) [src]
                                        /    ___\                                                       
                         ___   ____  2  |x*\/ 2 |                              _  /              |   4 \
  /                    \/ 2 *\/ pi *x *C|-------|    3                        |_  |   1/4, 3/4   | -x  |
 |                                      |   ____|   x *Gamma(1/4)*Gamma(3/4)* |   |              | ----|
 |  2    / 2\                           \ \/ pi /                            2  3 \1/2, 5/4, 7/4 |  4  /
 | x *cos\x / dx = C + -------------------------- - ----------------------------------------------------
 |                                 2                              8*Gamma(5/4)*Gamma(7/4)               
/                                                                                                       
x2cos(x2)dx=Cx3Γ(14)Γ(34)2F3(14,3412,54,74|x44)8Γ(54)Γ(74)+2πx2C(2xπ)2\int x^{2} \cos{\left(x^{2} \right)}\, dx = C - \frac{x^{3} \Gamma\left(\frac{1}{4}\right) \Gamma\left(\frac{3}{4}\right) {{}_{2}F_{3}\left(\begin{matrix} \frac{1}{4}, \frac{3}{4} \\ \frac{1}{2}, \frac{5}{4}, \frac{7}{4} \end{matrix}\middle| {- \frac{x^{4}}{4}} \right)}}{8 \Gamma\left(\frac{5}{4}\right) \Gamma\left(\frac{7}{4}\right)} + \frac{\sqrt{2} \sqrt{\pi} x^{2} C\left(\frac{\sqrt{2} x}{\sqrt{\pi}}\right)}{2}
Gráfica
0.001.000.100.200.300.400.500.600.700.800.900.01.0
Respuesta [src]
                                      /  ___ \           
                          ___   ____  |\/ 2  |           
                      3*\/ 2 *\/ pi *S|------|*Gamma(3/4)
                                      |  ____|           
3*Gamma(3/4)*sin(1)                   \\/ pi /           
------------------- - -----------------------------------
    8*Gamma(7/4)                 16*Gamma(7/4)           
32πS(2π)Γ(34)16Γ(74)+3sin(1)Γ(34)8Γ(74)- \frac{3 \sqrt{2} \sqrt{\pi} S\left(\frac{\sqrt{2}}{\sqrt{\pi}}\right) \Gamma\left(\frac{3}{4}\right)}{16 \Gamma\left(\frac{7}{4}\right)} + \frac{3 \sin{\left(1 \right)} \Gamma\left(\frac{3}{4}\right)}{8 \Gamma\left(\frac{7}{4}\right)}
=
=
                                      /  ___ \           
                          ___   ____  |\/ 2  |           
                      3*\/ 2 *\/ pi *S|------|*Gamma(3/4)
                                      |  ____|           
3*Gamma(3/4)*sin(1)                   \\/ pi /           
------------------- - -----------------------------------
    8*Gamma(7/4)                 16*Gamma(7/4)           
32πS(2π)Γ(34)16Γ(74)+3sin(1)Γ(34)8Γ(74)- \frac{3 \sqrt{2} \sqrt{\pi} S\left(\frac{\sqrt{2}}{\sqrt{\pi}}\right) \Gamma\left(\frac{3}{4}\right)}{16 \Gamma\left(\frac{7}{4}\right)} + \frac{3 \sin{\left(1 \right)} \Gamma\left(\frac{3}{4}\right)}{8 \Gamma\left(\frac{7}{4}\right)}
3*gamma(3/4)*sin(1)/(8*gamma(7/4)) - 3*sqrt(2)*sqrt(pi)*fresnels(sqrt(2)/sqrt(pi))*gamma(3/4)/(16*gamma(7/4))
Respuesta numérica [src]
0.265601341542258
0.265601341542258

    Estos ejemplos se pueden aplicar para introducción de los límites de integración inferior y superior.