Solución detallada
Tenemos la ecuación
$$\left(\left(z^{4} + 8\right) - 8 \sqrt{3} i\right) + 1 = 0$$
Ya que la potencia en la ecuación es igual a = 4 y miembro libre = -9 + 8*i*sqrt(3) complejo,
significa que la ecuación correspondiente no tiene soluciones reales
Las demás 4 raíces son complejas.
hacemos el cambio:
$$w = z$$
entonces la ecuación será así:
$$w^{4} = -9 + 8 \sqrt{3} i$$
Cualquier número complejo se puede presentar que:
$$w = r e^{i p}$$
sustituimos en la ecuación
$$r^{4} e^{4 i p} = -9 + 8 \sqrt{3} i$$
donde
$$r = \sqrt[8]{273}$$
- módulo del número complejo
Sustituyamos r:
$$e^{4 i p} = \frac{\sqrt{273} \left(-9 + 8 \sqrt{3} i\right)}{273}$$
Usando la fórmula de Euler hallemos las raíces para p
$$i \sin{\left(4 p \right)} + \cos{\left(4 p \right)} = \frac{\sqrt{273} \left(-9 + 8 \sqrt{3} i\right)}{273}$$
es decir
$$\cos{\left(4 p \right)} = - \frac{3 \sqrt{273}}{91}$$
y
$$\sin{\left(4 p \right)} = \frac{8 \sqrt{91}}{91}$$
entonces
$$p = \frac{\pi N}{2} - \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4}$$
donde N=0,1,2,3,...
Seleccionando los valores de N y sustituyendo p en la fórmula para w
Es decir, la solución será para w:
$$w_{1} = - \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
$$w_{2} = \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
$$w_{3} = - \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
$$w_{4} = \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
hacemos cambio inverso
$$w = z$$
$$z = w$$
Entonces la respuesta definitiva es:
$$z_{1} = - \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
$$z_{2} = \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
$$z_{3} = - \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
$$z_{4} = \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
/ / ___\ \ / / ___\ \
| |8*\/ 3 | | | |8*\/ 3 | |
| atan|-------| | | atan|-------| |
8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|
z1 = - \/ 273 *sin|- ------------- + --| + I*\/ 273 *cos|- ------------- + --|
\ 4 4 / \ 4 4 /
$$z_{1} = - \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
/ / ___\ \ / / ___\ \
| |8*\/ 3 | | | |8*\/ 3 | |
| atan|-------| | | atan|-------| |
8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|
z2 = \/ 273 *sin|- ------------- + --| - I*\/ 273 *cos|- ------------- + --|
\ 4 4 / \ 4 4 /
$$z_{2} = \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
/ / ___\ \ / / ___\ \
| |8*\/ 3 | | | |8*\/ 3 | |
| atan|-------| | | atan|-------| |
8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|
z3 = - \/ 273 *cos|- ------------- + --| - I*\/ 273 *sin|- ------------- + --|
\ 4 4 / \ 4 4 /
$$z_{3} = - \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
/ / ___\ \ / / ___\ \
| |8*\/ 3 | | | |8*\/ 3 | |
| atan|-------| | | atan|-------| |
8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|
z4 = \/ 273 *cos|- ------------- + --| + I*\/ 273 *sin|- ------------- + --|
\ 4 4 / \ 4 4 /
$$z_{4} = \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}$$
z4 = 273^(1/8)*cos(-atan(8*sqrt(3)/9)/4 + pi/4) + 273^(1/8)*i*sin(-atan(8*sqrt(3)/9)/4 + pi/4)
Suma y producto de raíces
[src]
/ / ___\ \ / / ___\ \ / / ___\ \ / / ___\ \ / / ___\ \ / / ___\ \ / / ___\ \ / / ___\ \
| |8*\/ 3 | | | |8*\/ 3 | | | |8*\/ 3 | | | |8*\/ 3 | | | |8*\/ 3 | | | |8*\/ 3 | | | |8*\/ 3 | | | |8*\/ 3 | |
| atan|-------| | | atan|-------| | | atan|-------| | | atan|-------| | | atan|-------| | | atan|-------| | | atan|-------| | | atan|-------| |
8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|
- \/ 273 *sin|- ------------- + --| + I*\/ 273 *cos|- ------------- + --| + \/ 273 *sin|- ------------- + --| - I*\/ 273 *cos|- ------------- + --| + - \/ 273 *cos|- ------------- + --| - I*\/ 273 *sin|- ------------- + --| + \/ 273 *cos|- ------------- + --| + I*\/ 273 *sin|- ------------- + --|
\ 4 4 / \ 4 4 / \ 4 4 / \ 4 4 / \ 4 4 / \ 4 4 / \ 4 4 / \ 4 4 /
$$\left(\left(- \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right) + \left(\left(\sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right) + \left(- \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right)\right)\right) + \left(\sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right)$$
$$0$$
/ / / ___\ \ / / ___\ \\ / / / ___\ \ / / ___\ \\ / / / ___\ \ / / ___\ \\ / / / ___\ \ / / ___\ \\
| | |8*\/ 3 | | | |8*\/ 3 | || | | |8*\/ 3 | | | |8*\/ 3 | || | | |8*\/ 3 | | | |8*\/ 3 | || | | |8*\/ 3 | | | |8*\/ 3 | ||
| | atan|-------| | | atan|-------| || | | atan|-------| | | atan|-------| || | | atan|-------| | | atan|-------| || | | atan|-------| | | atan|-------| ||
| 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|| |8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|| | 8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi|| |8 _____ | \ 9 / pi| 8 _____ | \ 9 / pi||
|- \/ 273 *sin|- ------------- + --| + I*\/ 273 *cos|- ------------- + --||*|\/ 273 *sin|- ------------- + --| - I*\/ 273 *cos|- ------------- + --||*|- \/ 273 *cos|- ------------- + --| - I*\/ 273 *sin|- ------------- + --||*|\/ 273 *cos|- ------------- + --| + I*\/ 273 *sin|- ------------- + --||
\ \ 4 4 / \ 4 4 // \ \ 4 4 / \ 4 4 // \ \ 4 4 / \ 4 4 // \ \ 4 4 / \ 4 4 //
$$\left(- \sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right) \left(\sqrt[8]{273} \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right) \left(- \sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right) \left(\sqrt[8]{273} \cos{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + \sqrt[8]{273} i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right)$$
2 2
/ / / ___\ \ / / ___\\\ / / / ___\\ / / ___\ \\
| | |8*\/ 3 | | | |8*\/ 3 ||| | | |8*\/ 3 || | |8*\/ 3 | ||
| | atan|-------| | | atan|-------||| | | atan|-------|| | atan|-------| ||
_____ | | \ 9 / pi| |pi \ 9 /|| | |pi \ 9 /| | \ 9 / pi||
\/ 273 *|I*sin|- ------------- + --| + sin|-- + -------------|| *|- I*sin|-- + -------------| + sin|- ------------- + --||
\ \ 4 4 / \4 4 // \ \4 4 / \ 4 4 //
$$\sqrt{273} \left(\sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} - i \sin{\left(\frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right)^{2} \left(\sin{\left(\frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)} + i \sin{\left(- \frac{\operatorname{atan}{\left(\frac{8 \sqrt{3}}{9} \right)}}{4} + \frac{\pi}{4} \right)}\right)^{2}$$
sqrt(273)*(i*sin(-atan(8*sqrt(3)/9)/4 + pi/4) + sin(pi/4 + atan(8*sqrt(3)/9)/4))^2*(-i*sin(pi/4 + atan(8*sqrt(3)/9)/4) + sin(-atan(8*sqrt(3)/9)/4 + pi/4))^2
z1 = -1.7326620224252 - 1.0308715569218*i
z2 = 1.7326620224252 + 1.0308715569218*i
z3 = 1.0308715569218 - 1.7326620224252*i
z4 = -1.0308715569218 + 1.7326620224252*i
z4 = -1.0308715569218 + 1.7326620224252*i