Sr Examen

Integral de (sin(x)+sin(2x))*(sin(nx)) dx

Límites de integración:

interior superior
v

Gráfico:

interior superior

Definida a trozos:

Solución

Ha introducido [src]
 pi                                
  /                                
 |                                 
 |  (sin(x) + sin(2*x))*sin(n*x) dx
 |                                 
/                                  
0                                  
$$\int\limits_{0}^{\pi} \left(\sin{\left(x \right)} + \sin{\left(2 x \right)}\right) \sin{\left(n x \right)}\, dx$$
Integral((sin(x) + sin(2*x))*sin(n*x), (x, 0, pi))
Respuesta [src]
/            -pi                                      
|            ----               for Or(n = -2, n = -1)
|             2                                       
|                                                     
|             pi                                      
|             --                 for Or(n = 1, n = 2) 
<             2                                       
|                                                     
|                  2                                  
| 2*sin(pi*n)     n *sin(pi*n)                        
|------------- + -------------        otherwise       
|     4      2        4      2                        
\4 + n  - 5*n    4 + n  - 5*n                         
$$\begin{cases} - \frac{\pi}{2} & \text{for}\: n = -2 \vee n = -1 \\\frac{\pi}{2} & \text{for}\: n = 1 \vee n = 2 \\\frac{n^{2} \sin{\left(\pi n \right)}}{n^{4} - 5 n^{2} + 4} + \frac{2 \sin{\left(\pi n \right)}}{n^{4} - 5 n^{2} + 4} & \text{otherwise} \end{cases}$$
=
=
/            -pi                                      
|            ----               for Or(n = -2, n = -1)
|             2                                       
|                                                     
|             pi                                      
|             --                 for Or(n = 1, n = 2) 
<             2                                       
|                                                     
|                  2                                  
| 2*sin(pi*n)     n *sin(pi*n)                        
|------------- + -------------        otherwise       
|     4      2        4      2                        
\4 + n  - 5*n    4 + n  - 5*n                         
$$\begin{cases} - \frac{\pi}{2} & \text{for}\: n = -2 \vee n = -1 \\\frac{\pi}{2} & \text{for}\: n = 1 \vee n = 2 \\\frac{n^{2} \sin{\left(\pi n \right)}}{n^{4} - 5 n^{2} + 4} + \frac{2 \sin{\left(\pi n \right)}}{n^{4} - 5 n^{2} + 4} & \text{otherwise} \end{cases}$$
Piecewise((-pi/2, (n = -2)∨(n = -1)), (pi/2, (n = 1)∨(n = 2)), (2*sin(pi*n)/(4 + n^4 - 5*n^2) + n^2*sin(pi*n)/(4 + n^4 - 5*n^2), True))

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