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x^2-8xy+15y^2=19 la ecuación

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Solución numérica:

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Solución

Ha introducido [src]
 2               2     
x  - 8*x*y + 15*y  = 19
$$15 y^{2} + \left(x^{2} - 8 x y\right) = 19$$
Solución detallada
Transportemos el miembro derecho de la ecuación al
miembro izquierdo de la ecuación con el signo negativo.

La ecuación se convierte de
$$15 y^{2} + \left(x^{2} - 8 x y\right) = 19$$
en
$$\left(15 y^{2} + \left(x^{2} - 8 x y\right)\right) - 19 = 0$$
Es la ecuación de la forma
a*x^2 + b*x + c = 0

La ecuación cuadrática puede ser resuelta
con la ayuda del discriminante.
Las raíces de la ecuación cuadrática:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
donde D = b^2 - 4*a*c es el discriminante.
Como
$$a = 1$$
$$b = - 8 y$$
$$c = 15 y^{2} - 19$$
, entonces
D = b^2 - 4 * a * c = 

(-8*y)^2 - 4 * (1) * (-19 + 15*y^2) = 76 + 4*y^2

La ecuación tiene dos raíces.
x1 = (-b + sqrt(D)) / (2*a)

x2 = (-b - sqrt(D)) / (2*a)

o
$$x_{1} = 4 y + \frac{\sqrt{4 y^{2} + 76}}{2}$$
$$x_{2} = 4 y - \frac{\sqrt{4 y^{2} + 76}}{2}$$
Teorema de Cardano-Vieta
es ecuación cuadrática reducida
$$p x + q + x^{2} = 0$$
donde
$$p = \frac{b}{a}$$
$$p = - 8 y$$
$$q = \frac{c}{a}$$
$$q = 15 y^{2} - 19$$
Fórmulas de Cardano-Vieta
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 8 y$$
$$x_{1} x_{2} = 15 y^{2} - 19$$
Gráfica
Suma y producto de raíces [src]
suma
            /              ___________________________________________                                                \       ___________________________________________                                                               /              ___________________________________________                                                \       ___________________________________________                                                
            |             /                       2                       /     /                      2        2   \\|      /                       2                       /     /                      2        2   \\               |             /                       2                       /     /                      2        2   \\|      /                       2                       /     /                      2        2   \\
            |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||   4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/|               |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||   4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/|
4*re(y) + I*|4*im(y) - \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------|| - \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *cos|------------------------------------------| + 4*re(y) + I*|4*im(y) + \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------|| + \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *cos|------------------------------------------|
            \                                                             \                    2                     //                                                      \                    2                     /               \                                                             \                    2                     //                                                      \                    2                     /
$$\left(i \left(- \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) - \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \cos{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{re}{\left(y\right)}\right) + \left(i \left(\sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) + \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \cos{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{re}{\left(y\right)}\right)$$
=
            /              ___________________________________________                                                \     /              ___________________________________________                                                \
            |             /                       2                       /     /                      2        2   \\|     |             /                       2                       /     /                      2        2   \\|
            |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||     |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||
8*re(y) + I*|4*im(y) + \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------|| + I*|4*im(y) - \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------||
            \                                                             \                    2                     //     \                                                             \                    2                     //
$$i \left(- \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) + i \left(\sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) + 8 \operatorname{re}{\left(y\right)}$$
producto
/            /              ___________________________________________                                                \       ___________________________________________                                                \ /            /              ___________________________________________                                                \       ___________________________________________                                                \
|            |             /                       2                       /     /                      2        2   \\|      /                       2                       /     /                      2        2   \\| |            |             /                       2                       /     /                      2        2   \\|      /                       2                       /     /                      2        2   \\|
|            |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||   4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/|| |            |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||   4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||
|4*re(y) + I*|4*im(y) - \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------|| - \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *cos|------------------------------------------||*|4*re(y) + I*|4*im(y) + \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------|| + \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *cos|------------------------------------------||
\            \                                                             \                    2                     //                                                      \                    2                     // \            \                                                             \                    2                     //                                                      \                    2                     //
$$\left(i \left(- \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) - \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \cos{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{re}{\left(y\right)}\right) \left(i \left(\sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) + \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \cos{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{re}{\left(y\right)}\right)$$
=
           2           2                      
-19 - 15*im (y) + 15*re (y) + 30*I*im(y)*re(y)
$$15 \left(\operatorname{re}{\left(y\right)}\right)^{2} + 30 i \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)} - 15 \left(\operatorname{im}{\left(y\right)}\right)^{2} - 19$$
-19 - 15*im(y)^2 + 15*re(y)^2 + 30*i*im(y)*re(y)
Respuesta rápida [src]
                 /              ___________________________________________                                                \       ___________________________________________                                                
                 |             /                       2                       /     /                      2        2   \\|      /                       2                       /     /                      2        2   \\
                 |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||   4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/|
x1 = 4*re(y) + I*|4*im(y) - \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------|| - \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *cos|------------------------------------------|
                 \                                                             \                    2                     //                                                      \                    2                     /
$$x_{1} = i \left(- \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) - \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \cos{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{re}{\left(y\right)}$$
                 /              ___________________________________________                                                \       ___________________________________________                                                
                 |             /                       2                       /     /                      2        2   \\|      /                       2                       /     /                      2        2   \\
                 |          4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/||   4 /  /       2        2   \        2      2        |atan2\2*im(y)*re(y), 19 + re (y) - im (y)/|
x2 = 4*re(y) + I*|4*im(y) + \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *sin|------------------------------------------|| + \/   \19 + re (y) - im (y)/  + 4*im (y)*re (y) *cos|------------------------------------------|
                 \                                                             \                    2                     //                                                      \                    2                     /
$$x_{2} = i \left(\sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \sin{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{im}{\left(y\right)}\right) + \sqrt[4]{\left(\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19\right)^{2} + 4 \left(\operatorname{re}{\left(y\right)}\right)^{2} \left(\operatorname{im}{\left(y\right)}\right)^{2}} \cos{\left(\frac{\operatorname{atan_{2}}{\left(2 \operatorname{re}{\left(y\right)} \operatorname{im}{\left(y\right)},\left(\operatorname{re}{\left(y\right)}\right)^{2} - \left(\operatorname{im}{\left(y\right)}\right)^{2} + 19 \right)}}{2} \right)} + 4 \operatorname{re}{\left(y\right)}$$
x2 = i*(((re(y)^2 - im(y)^2 + 19)^2 + 4*re(y)^2*im(y)^2)^(1/4)*sin(atan2(2*re(y)*im(y, re(y)^2 - im(y)^2 + 19)/2) + 4*im(y)) + ((re(y)^2 - im(y)^2 + 19)^2 + 4*re(y)^2*im(y)^2)^(1/4)*cos(atan2(2*re(y)*im(y), re(y)^2 - im(y)^2 + 19)/2) + 4*re(y))