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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]
                               ___________     /                                  ___________\
                              /       ___      |                                 /       ___ |
                             /  1   \/ 5       |                         ___    /  1   \/ 5  |
                          3 /   - + -----      |          ___          \/ 3 *3 /   - + ----- |
             1            \/    2     2        |        \/ 3                 \/    2     2   |
x1 = ------------------ - ---------------- + I*|- ------------------ - ----------------------|
            ___________          2             |         ___________             2           |
           /       ___                         |        /       ___                          |
          /  1   \/ 5                          |       /  1   \/ 5                           |
     2*3 /   - + -----                         |  2*3 /   - + -----                          |
       \/    2     2                           \    \/    2     2                            /
$$x_{1} = - \frac{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} + \frac{1}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} - \frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}\right)$$
                               ___________     /                                ___________\
                              /       ___      |                               /       ___ |
                             /  1   \/ 5       |                       ___    /  1   \/ 5  |
                          3 /   - + -----      |        ___          \/ 3 *3 /   - + ----- |
             1            \/    2     2        |      \/ 3                 \/    2     2   |
x2 = ------------------ - ---------------- + I*|------------------ + ----------------------|
            ___________          2             |       ___________             2           |
           /       ___                         |      /       ___                          |
          /  1   \/ 5                          |     /  1   \/ 5                           |
     2*3 /   - + -----                         |2*3 /   - + -----                          |
       \/    2     2                           \  \/    2     2                            /
$$x_{2} = - \frac{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} + \frac{1}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + i \left(\frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2}\right)$$
          ___________                   
         /       ___                    
        /  1   \/ 5            1        
x3 = 3 /   - + -----  - ----------------
     \/    2     2           ___________
                            /       ___ 
                           /  1   \/ 5  
                        3 /   - + ----- 
                        \/    2     2   
$$x_{3} = - \frac{1}{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}$$
x3 = -1/(1/2 + sqrt(5)/2)^(1/3) + (1/2 + sqrt(5)/2)^(1/3)
Suma y producto de raíces [src]
suma
                          ___________     /                                  ___________\                             ___________     /                                ___________\                                      
                         /       ___      |                                 /       ___ |                            /       ___      |                               /       ___ |                                      
                        /  1   \/ 5       |                         ___    /  1   \/ 5  |                           /  1   \/ 5       |                       ___    /  1   \/ 5  |        ___________                   
                     3 /   - + -----      |          ___          \/ 3 *3 /   - + ----- |                        3 /   - + -----      |        ___          \/ 3 *3 /   - + ----- |       /       ___                    
        1            \/    2     2        |        \/ 3                 \/    2     2   |           1            \/    2     2        |      \/ 3                 \/    2     2   |      /  1   \/ 5            1        
------------------ - ---------------- + I*|- ------------------ - ----------------------| + ------------------ - ---------------- + I*|------------------ + ----------------------| + 3 /   - + -----  - ----------------
       ___________          2             |         ___________             2           |          ___________          2             |       ___________             2           |   \/    2     2           ___________
      /       ___                         |        /       ___                          |         /       ___                         |      /       ___                          |                          /       ___ 
     /  1   \/ 5                          |       /  1   \/ 5                           |        /  1   \/ 5                          |     /  1   \/ 5                           |                         /  1   \/ 5  
2*3 /   - + -----                         |  2*3 /   - + -----                          |   2*3 /   - + -----                         |2*3 /   - + -----                          |                      3 /   - + ----- 
  \/    2     2                           \    \/    2     2                            /     \/    2     2                           \  \/    2     2                            /                      \/    2     2   
$$\left(- \frac{1}{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}\right) + \left(\left(- \frac{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} + \frac{1}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} - \frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}\right)\right) + \left(- \frac{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} + \frac{1}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + i \left(\frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2}\right)\right)\right)$$
=
  /                                ___________\     /                                  ___________\
  |                               /       ___ |     |                                 /       ___ |
  |                       ___    /  1   \/ 5  |     |                         ___    /  1   \/ 5  |
  |        ___          \/ 3 *3 /   - + ----- |     |          ___          \/ 3 *3 /   - + ----- |
  |      \/ 3                 \/    2     2   |     |        \/ 3                 \/    2     2   |
I*|------------------ + ----------------------| + I*|- ------------------ - ----------------------|
  |       ___________             2           |     |         ___________             2           |
  |      /       ___                          |     |        /       ___                          |
  |     /  1   \/ 5                           |     |       /  1   \/ 5                           |
  |2*3 /   - + -----                          |     |  2*3 /   - + -----                          |
  \  \/    2     2                            /     \    \/    2     2                            /
$$i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} - \frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}\right) + i \left(\frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2}\right)$$
producto
/                          ___________     /                                  ___________\\ /                          ___________     /                                ___________\\                                      
|                         /       ___      |                                 /       ___ || |                         /       ___      |                               /       ___ ||                                      
|                        /  1   \/ 5       |                         ___    /  1   \/ 5  || |                        /  1   \/ 5       |                       ___    /  1   \/ 5  || /     ___________                   \
|                     3 /   - + -----      |          ___          \/ 3 *3 /   - + ----- || |                     3 /   - + -----      |        ___          \/ 3 *3 /   - + ----- || |    /       ___                    |
|        1            \/    2     2        |        \/ 3                 \/    2     2   || |        1            \/    2     2        |      \/ 3                 \/    2     2   || |   /  1   \/ 5            1        |
|------------------ - ---------------- + I*|- ------------------ - ----------------------||*|------------------ - ---------------- + I*|------------------ + ----------------------||*|3 /   - + -----  - ----------------|
|       ___________          2             |         ___________             2           || |       ___________          2             |       ___________             2           || |\/    2     2           ___________|
|      /       ___                         |        /       ___                          || |      /       ___                         |      /       ___                          || |                       /       ___ |
|     /  1   \/ 5                          |       /  1   \/ 5                           || |     /  1   \/ 5                          |     /  1   \/ 5                           || |                      /  1   \/ 5  |
|2*3 /   - + -----                         |  2*3 /   - + -----                          || |2*3 /   - + -----                         |2*3 /   - + -----                          || |                   3 /   - + ----- |
\  \/    2     2                           \    \/    2     2                            // \  \/    2     2                           \  \/    2     2                            // \                   \/    2     2   /
$$\left(- \frac{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} + \frac{1}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + i \left(\frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2}\right)\right) \left(- \frac{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} + \frac{1}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}{2} - \frac{\sqrt{3}}{2 \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}}\right)\right) \left(- \frac{1}{\sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}} + \sqrt[3]{\frac{1}{2} + \frac{\sqrt{5}}{2}}\right)$$
=
1
$$1$$
1
Respuesta numérica [src]
x1 = -0.161092677313043 + 1.75438095978372*i
x2 = -0.161092677313043 - 1.75438095978372*i
x3 = 0.322185354626086
x3 = 0.322185354626086
Gráfico
x^3+3x-1=0 la ecuación