18*x^3-16*x^2+550*x+144=0 la ecuación
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Solución
Teorema de Cardano-Vieta
reescribamos la ecuación
( 550 x + ( 18 x 3 − 16 x 2 ) ) + 144 = 0 \left(550 x + \left(18 x^{3} - 16 x^{2}\right)\right) + 144 = 0 ( 550 x + ( 18 x 3 − 16 x 2 ) ) + 144 = 0 de
a x 3 + b x 2 + c x + d = 0 a x^{3} + b x^{2} + c x + d = 0 a x 3 + b x 2 + c x + d = 0 como ecuación cúbica reducida
x 3 + b x 2 a + c x a + d a = 0 x^{3} + \frac{b x^{2}}{a} + \frac{c x}{a} + \frac{d}{a} = 0 x 3 + a b x 2 + a c x + a d = 0 x 3 − 8 x 2 9 + 275 x 9 + 8 = 0 x^{3} - \frac{8 x^{2}}{9} + \frac{275 x}{9} + 8 = 0 x 3 − 9 8 x 2 + 9 275 x + 8 = 0 p x 2 + q x + v + x 3 = 0 p x^{2} + q x + v + x^{3} = 0 p x 2 + q x + v + x 3 = 0 donde
p = b a p = \frac{b}{a} p = a b p = − 8 9 p = - \frac{8}{9} p = − 9 8 q = c a q = \frac{c}{a} q = a c q = 275 9 q = \frac{275}{9} q = 9 275 v = d a v = \frac{d}{a} v = a d v = 8 v = 8 v = 8 Fórmulas de Cardano-Vieta
x 1 + x 2 + x 3 = − p x_{1} + x_{2} + x_{3} = - p 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_{1} x_{3} + x_{2} x_{3} = q 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} = v x 1 x 2 x 3 = v x 1 + x 2 + x 3 = 8 9 x_{1} + x_{2} + x_{3} = \frac{8}{9} x 1 + x 2 + x 3 = 9 8 x 1 x 2 + x 1 x 3 + x 2 x 3 = 275 9 x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = \frac{275}{9} x 1 x 2 + x 1 x 3 + x 2 x 3 = 9 275 x 1 x 2 x 3 = 8 x_{1} x_{2} x_{3} = 8 x 1 x 2 x 3 = 8
Suma y producto de raíces
[src]
________________________ / ________________________ \ ________________________ / ________________________\ ________________________
/ ___________ | / ___________ | / ___________ | / ___________ | / ___________
/ 167320 \/ 585523689 | ___ / 167320 \/ 585523689 | / 167320 \/ 585523689 | ___ / 167320 \/ 585523689 | / 167320 \/ 585523689
3 / ------ + ------------- |\/ 3 *3 / ------ + ------------- ___ | 3 / ------ + ------------- | ___ \/ 3 *3 / ------ + ------------- | 3 / ------ + -------------
8 7361 \/ 729 27 | \/ 729 27 7361*\/ 3 | 8 7361 \/ 729 27 | 7361*\/ 3 \/ 729 27 | 8 \/ 729 27 7361
-- - --------------------------------- + ----------------------------- + I*|----------------------------------- + ---------------------------------| + -- - --------------------------------- + ----------------------------- + I*|- --------------------------------- - -----------------------------------| + -- - ----------------------------- + ---------------------------------
27 ________________________ 6 | 6 ________________________| 27 ________________________ 6 | ________________________ 6 | 27 3 ________________________
/ ___________ | / ___________ | / ___________ | / ___________ | / ___________
/ 167320 \/ 585523689 | / 167320 \/ 585523689 | / 167320 \/ 585523689 | / 167320 \/ 585523689 | / 167320 \/ 585523689
486*3 / ------ + ------------- | 486*3 / ------ + ------------- | 486*3 / ------ + ------------- | 486*3 / ------ + ------------- | 243*3 / ------ + -------------
\/ 729 27 \ \/ 729 27 / \/ 729 27 \ \/ 729 27 / \/ 729 27
( − 167320 729 + 585523689 27 3 3 + 8 27 + 7361 243 167320 729 + 585523689 27 3 ) + ( ( − 7361 486 167320 729 + 585523689 27 3 + 8 27 + 167320 729 + 585523689 27 3 6 + i ( − 3 167320 729 + 585523689 27 3 6 − 7361 3 486 167320 729 + 585523689 27 3 ) ) + ( − 7361 486 167320 729 + 585523689 27 3 + 8 27 + 167320 729 + 585523689 27 3 6 + i ( 7361 3 486 167320 729 + 585523689 27 3 + 3 167320 729 + 585523689 27 3 6 ) ) ) \left(- \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{3} + \frac{8}{27} + \frac{7361}{243 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}\right) + \left(\left(- \frac{7361}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{8}{27} + \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} - \frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}\right)\right) + \left(- \frac{7361}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{8}{27} + \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} + i \left(\frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6}\right)\right)\right) − 3 3 729 167320 + 27 585523689 + 27 8 + 243 3 729 167320 + 27 585523689 7361 + − 486 3 729 167320 + 27 585523689 7361 + 27 8 + 6 3 729 167320 + 27 585523689 + i − 6 3 3 729 167320 + 27 585523689 − 486 3 729 167320 + 27 585523689 7361 3 + − 486 3 729 167320 + 27 585523689 7361 + 27 8 + 6 3 729 167320 + 27 585523689 + i 486 3 729 167320 + 27 585523689 7361 3 + 6 3 3 729 167320 + 27 585523689
/ ________________________\ / ________________________ \
| / ___________ | | / ___________ |
| ___ / 167320 \/ 585523689 | | ___ / 167320 \/ 585523689 |
| ___ \/ 3 *3 / ------ + ------------- | |\/ 3 *3 / ------ + ------------- ___ |
8 | 7361*\/ 3 \/ 729 27 | | \/ 729 27 7361*\/ 3 |
- + I*|- --------------------------------- - -----------------------------------| + I*|----------------------------------- + ---------------------------------|
9 | ________________________ 6 | | 6 ________________________|
| / ___________ | | / ___________ |
| / 167320 \/ 585523689 | | / 167320 \/ 585523689 |
| 486*3 / ------ + ------------- | | 486*3 / ------ + ------------- |
\ \/ 729 27 / \ \/ 729 27 /
8 9 + i ( − 3 167320 729 + 585523689 27 3 6 − 7361 3 486 167320 729 + 585523689 27 3 ) + i ( 7361 3 486 167320 729 + 585523689 27 3 + 3 167320 729 + 585523689 27 3 6 ) \frac{8}{9} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} - \frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}\right) + i \left(\frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6}\right) 9 8 + i − 6 3 3 729 167320 + 27 585523689 − 486 3 729 167320 + 27 585523689 7361 3 + i 486 3 729 167320 + 27 585523689 7361 3 + 6 3 3 729 167320 + 27 585523689
/ ________________________ / ________________________ \\ / ________________________ / ________________________\\ / ________________________ \
| / ___________ | / ___________ || | / ___________ | / ___________ || | / ___________ |
| / 167320 \/ 585523689 | ___ / 167320 \/ 585523689 || | / 167320 \/ 585523689 | ___ / 167320 \/ 585523689 || | / 167320 \/ 585523689 |
| 3 / ------ + ------------- |\/ 3 *3 / ------ + ------------- ___ || | 3 / ------ + ------------- | ___ \/ 3 *3 / ------ + ------------- || | 3 / ------ + ------------- |
|8 7361 \/ 729 27 | \/ 729 27 7361*\/ 3 || |8 7361 \/ 729 27 | 7361*\/ 3 \/ 729 27 || |8 \/ 729 27 7361 |
|-- - --------------------------------- + ----------------------------- + I*|----------------------------------- + ---------------------------------||*|-- - --------------------------------- + ----------------------------- + I*|- --------------------------------- - -----------------------------------||*|-- - ----------------------------- + ---------------------------------|
|27 ________________________ 6 | 6 ________________________|| |27 ________________________ 6 | ________________________ 6 || |27 3 ________________________|
| / ___________ | / ___________ || | / ___________ | / ___________ || | / ___________ |
| / 167320 \/ 585523689 | / 167320 \/ 585523689 || | / 167320 \/ 585523689 | / 167320 \/ 585523689 || | / 167320 \/ 585523689 |
| 486*3 / ------ + ------------- | 486*3 / ------ + ------------- || | 486*3 / ------ + ------------- | 486*3 / ------ + ------------- || | 243*3 / ------ + ------------- |
\ \/ 729 27 \ \/ 729 27 // \ \/ 729 27 \ \/ 729 27 // \ \/ 729 27 /
( − 7361 486 167320 729 + 585523689 27 3 + 8 27 + 167320 729 + 585523689 27 3 6 + i ( 7361 3 486 167320 729 + 585523689 27 3 + 3 167320 729 + 585523689 27 3 6 ) ) ( − 7361 486 167320 729 + 585523689 27 3 + 8 27 + 167320 729 + 585523689 27 3 6 + i ( − 3 167320 729 + 585523689 27 3 6 − 7361 3 486 167320 729 + 585523689 27 3 ) ) ( − 167320 729 + 585523689 27 3 3 + 8 27 + 7361 243 167320 729 + 585523689 27 3 ) \left(- \frac{7361}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{8}{27} + \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} + i \left(\frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6}\right)\right) \left(- \frac{7361}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{8}{27} + \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} - \frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}\right)\right) \left(- \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{3} + \frac{8}{27} + \frac{7361}{243 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}\right) − 486 3 729 167320 + 27 585523689 7361 + 27 8 + 6 3 729 167320 + 27 585523689 + i 486 3 729 167320 + 27 585523689 7361 3 + 6 3 3 729 167320 + 27 585523689 − 486 3 729 167320 + 27 585523689 7361 + 27 8 + 6 3 729 167320 + 27 585523689 + i − 6 3 3 729 167320 + 27 585523689 − 486 3 729 167320 + 27 585523689 7361 3 − 3 3 729 167320 + 27 585523689 + 27 8 + 243 3 729 167320 + 27 585523689 7361
________________________ / ________________________ \
/ ___________ | / ___________ |
/ 167320 \/ 585523689 | ___ / 167320 \/ 585523689 |
3 / ------ + ------------- |\/ 3 *3 / ------ + ------------- ___ |
8 7361 \/ 729 27 | \/ 729 27 7361*\/ 3 |
x1 = -- - --------------------------------- + ----------------------------- + I*|----------------------------------- + ---------------------------------|
27 ________________________ 6 | 6 ________________________|
/ ___________ | / ___________ |
/ 167320 \/ 585523689 | / 167320 \/ 585523689 |
486*3 / ------ + ------------- | 486*3 / ------ + ------------- |
\/ 729 27 \ \/ 729 27 /
x 1 = − 7361 486 167320 729 + 585523689 27 3 + 8 27 + 167320 729 + 585523689 27 3 6 + i ( 7361 3 486 167320 729 + 585523689 27 3 + 3 167320 729 + 585523689 27 3 6 ) x_{1} = - \frac{7361}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{8}{27} + \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} + i \left(\frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6}\right) x 1 = − 486 3 729 167320 + 27 585523689 7361 + 27 8 + 6 3 729 167320 + 27 585523689 + i 486 3 729 167320 + 27 585523689 7361 3 + 6 3 3 729 167320 + 27 585523689
________________________ / ________________________\
/ ___________ | / ___________ |
/ 167320 \/ 585523689 | ___ / 167320 \/ 585523689 |
3 / ------ + ------------- | ___ \/ 3 *3 / ------ + ------------- |
8 7361 \/ 729 27 | 7361*\/ 3 \/ 729 27 |
x2 = -- - --------------------------------- + ----------------------------- + I*|- --------------------------------- - -----------------------------------|
27 ________________________ 6 | ________________________ 6 |
/ ___________ | / ___________ |
/ 167320 \/ 585523689 | / 167320 \/ 585523689 |
486*3 / ------ + ------------- | 486*3 / ------ + ------------- |
\/ 729 27 \ \/ 729 27 /
x 2 = − 7361 486 167320 729 + 585523689 27 3 + 8 27 + 167320 729 + 585523689 27 3 6 + i ( − 3 167320 729 + 585523689 27 3 6 − 7361 3 486 167320 729 + 585523689 27 3 ) x_{2} = - \frac{7361}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} + \frac{8}{27} + \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} + i \left(- \frac{\sqrt{3} \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{6} - \frac{7361 \sqrt{3}}{486 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}\right) x 2 = − 486 3 729 167320 + 27 585523689 7361 + 27 8 + 6 3 729 167320 + 27 585523689 + i − 6 3 3 729 167320 + 27 585523689 − 486 3 729 167320 + 27 585523689 7361 3
________________________
/ ___________
/ 167320 \/ 585523689
3 / ------ + -------------
8 \/ 729 27 7361
x3 = -- - ----------------------------- + ---------------------------------
27 3 ________________________
/ ___________
/ 167320 \/ 585523689
243*3 / ------ + -------------
\/ 729 27
x 3 = − 167320 729 + 585523689 27 3 3 + 8 27 + 7361 243 167320 729 + 585523689 27 3 x_{3} = - \frac{\sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}}{3} + \frac{8}{27} + \frac{7361}{243 \sqrt[3]{\frac{167320}{729} + \frac{\sqrt{585523689}}{27}}} x 3 = − 3 3 729 167320 + 27 585523689 + 27 8 + 243 3 729 167320 + 27 585523689 7361
x3 = -(167320/729 + sqrt(585523689)/27)^(1/3)/3 + 8/27 + 7361/(243*(167320/729 + sqrt(585523689)/27)^(1/3))
x2 = 0.574090348339245 - 5.52482485478139*i
x3 = 0.574090348339245 + 5.52482485478139*i
x3 = 0.574090348339245 + 5.52482485478139*i