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Integral de (2x+1)*exp(-(x(x+1))/a) dx

Límites de integración:

interior superior
v

Gráfico:

interior superior

Definida a trozos:

Solución

Ha introducido [src]
 oo                          
  /                          
 |                           
 |             -x*(x + 1)    
 |             -----------   
 |                  a        
 |  (2*x + 1)*e            dx
 |                           
/                            
0                            
0(2x+1)e(1)x(x+1)adx\int\limits_{0}^{\infty} \left(2 x + 1\right) e^{\frac{\left(-1\right) x \left(x + 1\right)}{a}}\, dx
Integral((2*x + 1)*exp((-x*(x + 1))/a), (x, 0, oo))
Solución detallada
  1. que u=(1)x(x+1)au = \frac{\left(-1\right) x \left(x + 1\right)}{a}.

    Luego que du=(2x1)dxadu = \frac{\left(- 2 x - 1\right) dx}{a} y ponemos adu- a du:

    (aeu)du\int \left(- a e^{u}\right)\, du

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

      eudu=aeudu\int e^{u}\, du = - a \int e^{u}\, du

      1. La integral de la función exponencial es la mesma.

        eudu=eu\int e^{u}\, du = e^{u}

      Por lo tanto, el resultado es: aeu- a e^{u}

    Si ahora sustituir uu más en:

    ae(1)x(x+1)a- a e^{\frac{\left(-1\right) x \left(x + 1\right)}{a}}

  2. Ahora simplificar:

    aex(x+1)a- a e^{- \frac{x \left(x + 1\right)}{a}}

  3. Añadimos la constante de integración:

    aex(x+1)a+constant- a e^{- \frac{x \left(x + 1\right)}{a}}+ \mathrm{constant}


Respuesta:

aex(x+1)a+constant- a e^{- \frac{x \left(x + 1\right)}{a}}+ \mathrm{constant}

Respuesta (Indefinida) [src]
  /                                              
 |                                               
 |            -x*(x + 1)              -x*(x + 1) 
 |            -----------             -----------
 |                 a                       a     
 | (2*x + 1)*e            dx = C - a*e           
 |                                               
/                                                
(2x+1)e(1)x(x+1)adx=Cae(1)x(x+1)a\int \left(2 x + 1\right) e^{\frac{\left(-1\right) x \left(x + 1\right)}{a}}\, dx = C - a e^{\frac{\left(-1\right) x \left(x + 1\right)}{a}}
Respuesta [src]
/                                                                              1                                                                                                                                         
|                                                                             ---                                                                                                                                        
|      /               ____     /   1   \\          ____   ___     /   1   \  4*a                                                                                                                                        
|      |       -1    \/ pi *erfc|-------||   1    \/ pi *\/ a *erfc|-------|*e                                                                                                                                           
|      |       ---              |    ___||  ---                    |    ___|                                                                                                                                             
|  ___ |  ___  4*a              \2*\/ a /|  4*a                    \2*\/ a /             /   /            pi                 \     /                             pi\     /           pi                 \             pi\
|\/ a *|\/ a *e    - --------------------|*e    + -------------------------------  for Or|And||arg(a)| <= --, 2*|arg(a)| < pi|, And|2*|arg(a)| <= pi, |arg(a)| < --|, And||arg(a)| < --, 2*|arg(a)| < pi|, |arg(a)| < --|
|      \                      2          /                       2                       \   \            2                  /     \                             2 /     \           2                  /             2 /
|                                                                                                                                                                                                                        
<                          oo                                                                                                                                                                                            
|                           /                                                                                                                                                                                            
|                          |                                                                                                                                                                                             
|                          |             -x*(1 + x)                                                                                                                                                                      
|                          |             -----------                                                                                                                                                                     
|                          |                  a                                                                                                                                                                          
|                          |  (1 + 2*x)*e            dx                                                                                          otherwise                                                               
|                          |                                                                                                                                                                                             
|                         /                                                                                                                                                                                              
\                         0                                                                                                                                                                                              
{a(ae14aπerfc(12a)2)e14a+πae14aerfc(12a)2for(arg(a)π22arg(a)<π)(2arg(a)πarg(a)<π2)(arg(a)<π22arg(a)<π)arg(a)<π20(2x+1)ex(x+1)adxotherwise\begin{cases} \sqrt{a} \left(\sqrt{a} e^{- \frac{1}{4 a}} - \frac{\sqrt{\pi} \operatorname{erfc}{\left(\frac{1}{2 \sqrt{a}} \right)}}{2}\right) e^{\frac{1}{4 a}} + \frac{\sqrt{\pi} \sqrt{a} e^{\frac{1}{4 a}} \operatorname{erfc}{\left(\frac{1}{2 \sqrt{a}} \right)}}{2} & \text{for}\: \left(\left|{\arg{\left(a \right)}}\right| \leq \frac{\pi}{2} \wedge 2 \left|{\arg{\left(a \right)}}\right| < \pi\right) \vee \left(2 \left|{\arg{\left(a \right)}}\right| \leq \pi \wedge \left|{\arg{\left(a \right)}}\right| < \frac{\pi}{2}\right) \vee \left(\left|{\arg{\left(a \right)}}\right| < \frac{\pi}{2} \wedge 2 \left|{\arg{\left(a \right)}}\right| < \pi\right) \vee \left|{\arg{\left(a \right)}}\right| < \frac{\pi}{2} \\\int\limits_{0}^{\infty} \left(2 x + 1\right) e^{- \frac{x \left(x + 1\right)}{a}}\, dx & \text{otherwise} \end{cases}
=
=
/                                                                              1                                                                                                                                         
|                                                                             ---                                                                                                                                        
|      /               ____     /   1   \\          ____   ___     /   1   \  4*a                                                                                                                                        
|      |       -1    \/ pi *erfc|-------||   1    \/ pi *\/ a *erfc|-------|*e                                                                                                                                           
|      |       ---              |    ___||  ---                    |    ___|                                                                                                                                             
|  ___ |  ___  4*a              \2*\/ a /|  4*a                    \2*\/ a /             /   /            pi                 \     /                             pi\     /           pi                 \             pi\
|\/ a *|\/ a *e    - --------------------|*e    + -------------------------------  for Or|And||arg(a)| <= --, 2*|arg(a)| < pi|, And|2*|arg(a)| <= pi, |arg(a)| < --|, And||arg(a)| < --, 2*|arg(a)| < pi|, |arg(a)| < --|
|      \                      2          /                       2                       \   \            2                  /     \                             2 /     \           2                  /             2 /
|                                                                                                                                                                                                                        
<                          oo                                                                                                                                                                                            
|                           /                                                                                                                                                                                            
|                          |                                                                                                                                                                                             
|                          |             -x*(1 + x)                                                                                                                                                                      
|                          |             -----------                                                                                                                                                                     
|                          |                  a                                                                                                                                                                          
|                          |  (1 + 2*x)*e            dx                                                                                          otherwise                                                               
|                          |                                                                                                                                                                                             
|                         /                                                                                                                                                                                              
\                         0                                                                                                                                                                                              
{a(ae14aπerfc(12a)2)e14a+πae14aerfc(12a)2for(arg(a)π22arg(a)<π)(2arg(a)πarg(a)<π2)(arg(a)<π22arg(a)<π)arg(a)<π20(2x+1)ex(x+1)adxotherwise\begin{cases} \sqrt{a} \left(\sqrt{a} e^{- \frac{1}{4 a}} - \frac{\sqrt{\pi} \operatorname{erfc}{\left(\frac{1}{2 \sqrt{a}} \right)}}{2}\right) e^{\frac{1}{4 a}} + \frac{\sqrt{\pi} \sqrt{a} e^{\frac{1}{4 a}} \operatorname{erfc}{\left(\frac{1}{2 \sqrt{a}} \right)}}{2} & \text{for}\: \left(\left|{\arg{\left(a \right)}}\right| \leq \frac{\pi}{2} \wedge 2 \left|{\arg{\left(a \right)}}\right| < \pi\right) \vee \left(2 \left|{\arg{\left(a \right)}}\right| \leq \pi \wedge \left|{\arg{\left(a \right)}}\right| < \frac{\pi}{2}\right) \vee \left(\left|{\arg{\left(a \right)}}\right| < \frac{\pi}{2} \wedge 2 \left|{\arg{\left(a \right)}}\right| < \pi\right) \vee \left|{\arg{\left(a \right)}}\right| < \frac{\pi}{2} \\\int\limits_{0}^{\infty} \left(2 x + 1\right) e^{- \frac{x \left(x + 1\right)}{a}}\, dx & \text{otherwise} \end{cases}
Piecewise((sqrt(a)*(sqrt(a)*exp(-1/(4*a)) - sqrt(pi)*erfc(1/(2*sqrt(a)))/2)*exp(1/(4*a)) + sqrt(pi)*sqrt(a)*erfc(1/(2*sqrt(a)))*exp(1/(4*a))/2, (Abs(arg(a)) < pi/2)∨((Abs(arg(a)) <= pi/2)∧(2*Abs(arg(a)) < pi))∨((2*Abs(arg(a)) <= pi)∧(Abs(arg(a)) < pi/2))∨((Abs(arg(a)) < pi/2)∧(2*Abs(arg(a)) < pi))), (Integral((1 + 2*x)*exp(-x*(1 + x)/a), (x, 0, oo)), True))

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