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x^3+3x+1=0

x^3+3x+1=0 la ecuación

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Solución numérica:

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Solución

Ha introducido [src]
 3              
x  + 3*x + 1 = 0
$$\left(x^{3} + 3 x\right) + 1 = 0$$
Teorema de Cardano-Vieta
es ecuación cúbica reducida
$$p x^{2} + q x + v + x^{3} = 0$$
donde
$$p = \frac{b}{a}$$
$$p = 0$$
$$q = \frac{c}{a}$$
$$q = 3$$
$$v = \frac{d}{a}$$
$$v = 1$$
Fórmulas de Cardano-Vieta
$$x_{1} + x_{2} + x_{3} = - p$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = q$$
$$x_{1} x_{2} x_{3} = v$$
$$x_{1} + x_{2} + x_{3} = 0$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = 3$$
$$x_{1} x_{2} x_{3} = 1$$
Gráfica
Respuesta rápida [src]
                                     _______________     /           _______________                         \
                                    /           ___      |          /           ___                          |
                                   /  27   27*\/ 5       |  ___    /  27   27*\/ 5                           |
                                3 /   -- + --------      |\/ 3 *3 /   -- + --------               ___        |
                 3              \/    2       2          |      \/    2       2               3*\/ 3         |
x1 = - ---------------------- + -------------------- + I*|-------------------------- + ----------------------|
              _______________            6               |            6                       _______________|
             /           ___                             |                                   /           ___ |
            /  27   27*\/ 5                              |                                  /  27   27*\/ 5  |
       2*3 /   -- + --------                             |                             2*3 /   -- + -------- |
         \/    2       2                                 \                               \/    2       2     /
$$x_{1} = - \frac{3}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} + i \left(\frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6}\right)$$
                                     _______________     /                                      _______________\
                                    /           ___      |                                     /           ___ |
                                   /  27   27*\/ 5       |                             ___    /  27   27*\/ 5  |
                                3 /   -- + --------      |             ___           \/ 3 *3 /   -- + -------- |
                 3              \/    2       2          |         3*\/ 3                  \/    2       2     |
x2 = - ---------------------- + -------------------- + I*|- ---------------------- - --------------------------|
              _______________            6               |         _______________               6             |
             /           ___                             |        /           ___                              |
            /  27   27*\/ 5                              |       /  27   27*\/ 5                               |
       2*3 /   -- + --------                             |  2*3 /   -- + --------                              |
         \/    2       2                                 \    \/    2       2                                  /
$$x_{2} = - \frac{3}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} - \frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}\right)$$
                                 _______________
                                /           ___ 
                               /  27   27*\/ 5  
                            3 /   -- + -------- 
              3             \/    2       2     
x3 = -------------------- - --------------------
          _______________            3          
         /           ___                        
        /  27   27*\/ 5                         
     3 /   -- + --------                        
     \/    2       2                            
$$x_{3} = - \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{3} + \frac{3}{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}$$
x3 = -(27/2 + 27*sqrt(5)/2)^(1/3)/3 + 3/(27/2 + 27*sqrt(5)/2)^(1/3)
Suma y producto de raíces [src]
suma
                                _______________     /           _______________                         \                                   _______________     /                                      _______________\                               _______________
                               /           ___      |          /           ___                          |                                  /           ___      |                                     /           ___ |                              /           ___ 
                              /  27   27*\/ 5       |  ___    /  27   27*\/ 5                           |                                 /  27   27*\/ 5       |                             ___    /  27   27*\/ 5  |                             /  27   27*\/ 5  
                           3 /   -- + --------      |\/ 3 *3 /   -- + --------               ___        |                              3 /   -- + --------      |             ___           \/ 3 *3 /   -- + -------- |                          3 /   -- + -------- 
            3              \/    2       2          |      \/    2       2               3*\/ 3         |               3              \/    2       2          |         3*\/ 3                  \/    2       2     |            3             \/    2       2     
- ---------------------- + -------------------- + I*|-------------------------- + ----------------------| + - ---------------------- + -------------------- + I*|- ---------------------- - --------------------------| + -------------------- - --------------------
         _______________            6               |            6                       _______________|            _______________            6               |         _______________               6             |        _______________            3          
        /           ___                             |                                   /           ___ |           /           ___                             |        /           ___                              |       /           ___                        
       /  27   27*\/ 5                              |                                  /  27   27*\/ 5  |          /  27   27*\/ 5                              |       /  27   27*\/ 5                               |      /  27   27*\/ 5                         
  2*3 /   -- + --------                             |                             2*3 /   -- + -------- |     2*3 /   -- + --------                             |  2*3 /   -- + --------                              |   3 /   -- + --------                        
    \/    2       2                                 \                               \/    2       2     /       \/    2       2                                 \    \/    2       2                                  /   \/    2       2                            
$$\left(- \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{3} + \frac{3}{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}\right) + \left(\left(- \frac{3}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} - \frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}\right)\right) + \left(- \frac{3}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} + i \left(\frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6}\right)\right)\right)$$
=
  /                                      _______________\     /           _______________                         \
  |                                     /           ___ |     |          /           ___                          |
  |                             ___    /  27   27*\/ 5  |     |  ___    /  27   27*\/ 5                           |
  |             ___           \/ 3 *3 /   -- + -------- |     |\/ 3 *3 /   -- + --------               ___        |
  |         3*\/ 3                  \/    2       2     |     |      \/    2       2               3*\/ 3         |
I*|- ---------------------- - --------------------------| + I*|-------------------------- + ----------------------|
  |         _______________               6             |     |            6                       _______________|
  |        /           ___                              |     |                                   /           ___ |
  |       /  27   27*\/ 5                               |     |                                  /  27   27*\/ 5  |
  |  2*3 /   -- + --------                              |     |                             2*3 /   -- + -------- |
  \    \/    2       2                                  /     \                               \/    2       2     /
$$i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} - \frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}\right) + i \left(\frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6}\right)$$
producto
/                                _______________     /           _______________                         \\ /                                _______________     /                                      _______________\\ /                            _______________\
|                               /           ___      |          /           ___                          || |                               /           ___      |                                     /           ___ || |                           /           ___ |
|                              /  27   27*\/ 5       |  ___    /  27   27*\/ 5                           || |                              /  27   27*\/ 5       |                             ___    /  27   27*\/ 5  || |                          /  27   27*\/ 5  |
|                           3 /   -- + --------      |\/ 3 *3 /   -- + --------               ___        || |                           3 /   -- + --------      |             ___           \/ 3 *3 /   -- + -------- || |                       3 /   -- + -------- |
|            3              \/    2       2          |      \/    2       2               3*\/ 3         || |            3              \/    2       2          |         3*\/ 3                  \/    2       2     || |         3             \/    2       2     |
|- ---------------------- + -------------------- + I*|-------------------------- + ----------------------||*|- ---------------------- + -------------------- + I*|- ---------------------- - --------------------------||*|-------------------- - --------------------|
|         _______________            6               |            6                       _______________|| |         _______________            6               |         _______________               6             || |     _______________            3          |
|        /           ___                             |                                   /           ___ || |        /           ___                             |        /           ___                              || |    /           ___                        |
|       /  27   27*\/ 5                              |                                  /  27   27*\/ 5  || |       /  27   27*\/ 5                              |       /  27   27*\/ 5                               || |   /  27   27*\/ 5                         |
|  2*3 /   -- + --------                             |                             2*3 /   -- + -------- || |  2*3 /   -- + --------                             |  2*3 /   -- + --------                              || |3 /   -- + --------                        |
\    \/    2       2                                 \                               \/    2       2     // \    \/    2       2                                 \    \/    2       2                                  // \\/    2       2                            /
$$\left(- \frac{3}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} + i \left(\frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6}\right)\right) \left(- \frac{3}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}} + \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{6} - \frac{3 \sqrt{3}}{2 \sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}\right)\right) \left(- \frac{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}{3} + \frac{3}{\sqrt[3]{\frac{27}{2} + \frac{27 \sqrt{5}}{2}}}\right)$$
=
-1
$$-1$$
-1
Respuesta numérica [src]
x1 = 0.161092677313043 + 1.75438095978372*i
x2 = -0.322185354626086
x3 = 0.161092677313043 - 1.75438095978372*i
x3 = 0.161092677313043 - 1.75438095978372*i
Gráfico
x^3+3x+1=0 la ecuación