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x^3-9*x^2+6*x-15=0 la ecuación

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Solución numérica:

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Solución

Ha introducido [src]
 3      2               
x  - 9*x  + 6*x - 15 = 0
$$\left(6 x + \left(x^{3} - 9 x^{2}\right)\right) - 15 = 0$$
Teorema de Cardano-Vieta
es ecuación cúbica reducida
$$p x^{2} + q x + v + x^{3} = 0$$
donde
$$p = \frac{b}{a}$$
$$p = -9$$
$$q = \frac{c}{a}$$
$$q = 6$$
$$v = \frac{d}{a}$$
$$v = -15$$
Fórmulas de Cardano-Vieta
$$x_{1} + x_{2} + x_{3} = - p$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = q$$
$$x_{1} x_{2} x_{3} = v$$
$$x_{1} + x_{2} + x_{3} = 9$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = 6$$
$$x_{1} x_{2} x_{3} = -15$$
Gráfica
Respuesta rápida [src]
                                       _______________     /             _______________                         \
                                      /        ______      |            /        ______                          |
                                     /  51   \/ 1229       |    ___    /  51   \/ 1229                           |
                                  3 /   -- + --------      |  \/ 3 *3 /   -- + --------               ___        |
                   7              \/    2       2          |        \/    2       2               7*\/ 3         |
x1 = 3 - ---------------------- - -------------------- + I*|- -------------------------- + ----------------------|
                _______________            2               |              2                       _______________|
               /        ______                             |                                     /        ______ |
              /  51   \/ 1229                              |                                    /  51   \/ 1229  |
         2*3 /   -- + --------                             |                               2*3 /   -- + -------- |
           \/    2       2                                 \                                 \/    2       2     /
$$x_{1} = - \frac{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} - \frac{7}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} + \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}\right)$$
                                       _______________     /           _______________                         \
                                      /        ______      |          /        ______                          |
                                     /  51   \/ 1229       |  ___    /  51   \/ 1229                           |
                                  3 /   -- + --------      |\/ 3 *3 /   -- + --------               ___        |
                   7              \/    2       2          |      \/    2       2               7*\/ 3         |
x2 = 3 - ---------------------- - -------------------- + I*|-------------------------- - ----------------------|
                _______________            2               |            2                       _______________|
               /        ______                             |                                   /        ______ |
              /  51   \/ 1229                              |                                  /  51   \/ 1229  |
         2*3 /   -- + --------                             |                             2*3 /   -- + -------- |
           \/    2       2                                 \                               \/    2       2     /
$$x_{2} = - \frac{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} - \frac{7}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + i \left(- \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2}\right)$$
              _______________                       
             /        ______                        
            /  51   \/ 1229              7          
x3 = 3 + 3 /   -- + --------  + --------------------
         \/    2       2             _______________
                                    /        ______ 
                                   /  51   \/ 1229  
                                3 /   -- + -------- 
                                \/    2       2     
$$x_{3} = \frac{7}{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}$$
x3 = 7/(sqrt(1229)/2 + 51/2)^(1/3) + 3 + (sqrt(1229)/2 + 51/2)^(1/3)
Suma y producto de raíces [src]
suma
                                  _______________     /             _______________                         \                                     _______________     /           _______________                         \                                                  
                                 /        ______      |            /        ______                          |                                    /        ______      |          /        ______                          |                                                  
                                /  51   \/ 1229       |    ___    /  51   \/ 1229                           |                                   /  51   \/ 1229       |  ___    /  51   \/ 1229                           |            _______________                       
                             3 /   -- + --------      |  \/ 3 *3 /   -- + --------               ___        |                                3 /   -- + --------      |\/ 3 *3 /   -- + --------               ___        |           /        ______                        
              7              \/    2       2          |        \/    2       2               7*\/ 3         |                 7              \/    2       2          |      \/    2       2               7*\/ 3         |          /  51   \/ 1229              7          
3 - ---------------------- - -------------------- + I*|- -------------------------- + ----------------------| + 3 - ---------------------- - -------------------- + I*|-------------------------- - ----------------------| + 3 + 3 /   -- + --------  + --------------------
           _______________            2               |              2                       _______________|              _______________            2               |            2                       _______________|       \/    2       2             _______________
          /        ______                             |                                     /        ______ |             /        ______                             |                                   /        ______ |                                  /        ______ 
         /  51   \/ 1229                              |                                    /  51   \/ 1229  |            /  51   \/ 1229                              |                                  /  51   \/ 1229  |                                 /  51   \/ 1229  
    2*3 /   -- + --------                             |                               2*3 /   -- + -------- |       2*3 /   -- + --------                             |                             2*3 /   -- + -------- |                              3 /   -- + -------- 
      \/    2       2                                 \                                 \/    2       2     /         \/    2       2                                 \                               \/    2       2     /                              \/    2       2     
$$\left(\frac{7}{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}\right) + \left(\left(- \frac{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} - \frac{7}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} + \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}\right)\right) + \left(- \frac{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} - \frac{7}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + i \left(- \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2}\right)\right)\right)$$
=
      /           _______________                         \     /             _______________                         \
      |          /        ______                          |     |            /        ______                          |
      |  ___    /  51   \/ 1229                           |     |    ___    /  51   \/ 1229                           |
      |\/ 3 *3 /   -- + --------               ___        |     |  \/ 3 *3 /   -- + --------               ___        |
      |      \/    2       2               7*\/ 3         |     |        \/    2       2               7*\/ 3         |
9 + I*|-------------------------- - ----------------------| + I*|- -------------------------- + ----------------------|
      |            2                       _______________|     |              2                       _______________|
      |                                   /        ______ |     |                                     /        ______ |
      |                                  /  51   \/ 1229  |     |                                    /  51   \/ 1229  |
      |                             2*3 /   -- + -------- |     |                               2*3 /   -- + -------- |
      \                               \/    2       2     /     \                                 \/    2       2     /
$$9 + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} + \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}\right) + i \left(- \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2}\right)$$
producto
/                                  _______________     /             _______________                         \\ /                                  _______________     /           _______________                         \\                                                  
|                                 /        ______      |            /        ______                          || |                                 /        ______      |          /        ______                          ||                                                  
|                                /  51   \/ 1229       |    ___    /  51   \/ 1229                           || |                                /  51   \/ 1229       |  ___    /  51   \/ 1229                           || /         _______________                       \
|                             3 /   -- + --------      |  \/ 3 *3 /   -- + --------               ___        || |                             3 /   -- + --------      |\/ 3 *3 /   -- + --------               ___        || |        /        ______                        |
|              7              \/    2       2          |        \/    2       2               7*\/ 3         || |              7              \/    2       2          |      \/    2       2               7*\/ 3         || |       /  51   \/ 1229              7          |
|3 - ---------------------- - -------------------- + I*|- -------------------------- + ----------------------||*|3 - ---------------------- - -------------------- + I*|-------------------------- - ----------------------||*|3 + 3 /   -- + --------  + --------------------|
|           _______________            2               |              2                       _______________|| |           _______________            2               |            2                       _______________|| |    \/    2       2             _______________|
|          /        ______                             |                                     /        ______ || |          /        ______                             |                                   /        ______ || |                               /        ______ |
|         /  51   \/ 1229                              |                                    /  51   \/ 1229  || |         /  51   \/ 1229                              |                                  /  51   \/ 1229  || |                              /  51   \/ 1229  |
|    2*3 /   -- + --------                             |                               2*3 /   -- + -------- || |    2*3 /   -- + --------                             |                             2*3 /   -- + -------- || |                           3 /   -- + -------- |
\      \/    2       2                                 \                                 \/    2       2     // \      \/    2       2                                 \                               \/    2       2     // \                           \/    2       2     /
$$\left(- \frac{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} - \frac{7}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + i \left(- \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2}\right)\right) \left(- \frac{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} - \frac{7}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}{2} + \frac{7 \sqrt{3}}{2 \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}}\right)\right) \left(\frac{7}{\sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}} + 3 + \sqrt[3]{\frac{\sqrt{1229}}{2} + \frac{51}{2}}\right)$$
=
15
$$15$$
15
Respuesta numérica [src]
x1 = 8.5017913555054
x2 = 0.2491043222473 + 1.30471494573928*i
x3 = 0.2491043222473 - 1.30471494573928*i
x3 = 0.2491043222473 - 1.30471494573928*i