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(x+5)(x+7)^2/x^2+2x+1<=0

(x+5)(x+7)^2/x^2+2x+1<=0 desigualdades

En la desigualdad la incógnita

Solución

Ha introducido [src]
               2               
(x + 5)*(x + 7)                
---------------- + 2*x + 1 <= 0
        2                      
       x                       
$$\left(2 x + \frac{\left(x + 5\right) \left(x + 7\right)^{2}}{x^{2}}\right) + 1 \leq 0$$
2*x + ((x + 5)*(x + 7)^2)/x^2 + 1 <= 0
Solución detallada
Se da la desigualdad:
$$\left(2 x + \frac{\left(x + 5\right) \left(x + 7\right)^{2}}{x^{2}}\right) + 1 \leq 0$$
Para resolver esta desigualdad primero hay que resolver la ecuación correspondiente:
$$\left(2 x + \frac{\left(x + 5\right) \left(x + 7\right)^{2}}{x^{2}}\right) + 1 = 0$$
Resolvemos:
$$x_{1} = - \frac{20}{9} + \frac{671}{27 \left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}} - \frac{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3}$$
$$x_{2} = - \frac{20}{9} - \frac{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} + \frac{671}{27 \left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}$$
$$x_{3} = - \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{20}{9} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}$$
Descartamos las soluciones complejas:
$$x_{1} = - \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{20}{9} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}$$
Las raíces dadas
$$x_{1} = - \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{20}{9} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}$$
son puntos de cambio del signo de desigualdad en las soluciones.
Primero definámonos con el signo hasta el punto extremo izquierdo:
$$x_{0} \leq x_{1}$$
Consideremos, por ejemplo, el punto
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$\left(- \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{20}{9} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}\right) + - \frac{1}{10}$$
=
$$- \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{209}{90} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}$$
lo sustituimos en la expresión
$$\left(2 x + \frac{\left(x + 5\right) \left(x + 7\right)^{2}}{x^{2}}\right) + 1 \leq 0$$
$$\left(2 \left(- \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{209}{90} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}\right) + \frac{\left(\left(- \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{209}{90} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}\right) + 5\right) \left(\left(- \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{209}{90} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}\right) + 7\right)^{2}}{\left(- \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{209}{90} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}\right)^{2}}\right) + 1 \leq 0$$
                                                                                                                                     2                                                                      
                                                                     /           ____________________                               \  /           ____________________                               \     
                                                                     |          /              _____                                |  |          /              _____                                |     
                                                                     |         /  11275   77*\/ 309                                 |  |         /  11275   77*\/ 309                                 |     
                                                                     |      3 /   ----- + ----------                                |  |      3 /   ----- + ----------                                |     
                                                                     |421   \/      54        2                     671             |  |241   \/      54        2                     671             |     
                                                                     |--- - ------------------------- + ----------------------------| *|--- - ------------------------- + ----------------------------|     
               ____________________                                  | 90               3                       ____________________|  | 90               3                       ____________________|     
              /              _____                                   |                                         /              _____ |  |                                         /              _____ |     
             /  11275   77*\/ 309                                    |                                        /  11275   77*\/ 309  |  |                                        /  11275   77*\/ 309  |     
        2*3 /   ----- + ----------                                   |                                  27*3 /   ----- + ---------- |  |                                  27*3 /   ----- + ---------- |     
  164     \/      54        2                     1342               \                                     \/      54        2      /  \                                     \/      54        2      /     
- --- - --------------------------- + ---------------------------- + ---------------------------------------------------------------------------------------------------------------------------------- <= 0
   45                3                        ____________________                                                                                                    2                                     
                                             /              _____                                   /             ____________________                               \                                      
                                            /  11275   77*\/ 309                                    |            /              _____                                |                                      
                                      27*3 /   ----- + ----------                                   |           /  11275   77*\/ 309                                 |                                      
                                         \/      54        2                                        |        3 /   ----- + ----------                                |                                      
                                                                                                    |  209   \/      54        2                     671             |                                      
                                                                                                    |- --- - ------------------------- + ----------------------------|                                      
                                                                                                    |   90               3                       ____________________|                                      
                                                                                                    |                                           /              _____ |                                      
                                                                                                    |                                          /  11275   77*\/ 309  |                                      
                                                                                                    |                                    27*3 /   ----- + ---------- |                                      
                                                                                                    \                                       \/      54        2      /                                      

significa que la solución de la desigualdad será con:
$$x \leq - \frac{\sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}{3} - \frac{20}{9} + \frac{671}{27 \sqrt[3]{\frac{11275}{54} + \frac{77 \sqrt{309}}{2}}}$$
 _____          
      \    
-------•-------
       x1
Solución de la desigualdad en el gráfico
Respuesta rápida 2 [src]
             /   3       2                 \ 
(-oo, CRootOf\3*x  + 20*x  + 119*x + 245, 0/]
$$x\ in\ \left(-\infty, \operatorname{CRootOf} {\left(3 x^{3} + 20 x^{2} + 119 x + 245, 0\right)}\right]$$
x in Interval(-oo, CRootOf(3*x^3 + 20*x^2 + 119*x + 245, 0))
Respuesta rápida [src]
   /            /   3       2                 \         \
And\x <= CRootOf\3*x  + 20*x  + 119*x + 245, 0/, -oo < x/
$$x \leq \operatorname{CRootOf} {\left(3 x^{3} + 20 x^{2} + 119 x + 245, 0\right)} \wedge -\infty < x$$
(-oo < x)∧(x <= CRootOf(3*x^3 + 20*x^2 + 119*x + 245, 0))
Gráfico
(x+5)(x+7)^2/x^2+2x+1<=0 desigualdades