Sr Examen

Integral de cosx*cos(n*x) dx

Límites de integración:

interior superior
v

Gráfico:

interior superior

Definida a trozos:

Solución

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

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