sqrt(3)*x^3+3*x^2-3*sqrt(3)*x-1=0 la ecuación
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Solución
Teorema de Cardano-Vieta
reescribamos la ecuación
( − 3 3 x + ( 3 x 3 + 3 x 2 ) ) − 1 = 0 \left(- 3 \sqrt{3} x + \left(\sqrt{3} x^{3} + 3 x^{2}\right)\right) - 1 = 0 ( − 3 3 x + ( 3 x 3 + 3 x 2 ) ) − 1 = 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 3 ( 3 x 3 + 3 x 2 − 3 3 x − 1 ) 3 = 0 \frac{\sqrt{3} \left(\sqrt{3} x^{3} + 3 x^{2} - 3 \sqrt{3} x - 1\right)}{3} = 0 3 3 ( 3 x 3 + 3 x 2 − 3 3 x − 1 ) = 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 = 3 p = \sqrt{3} p = 3 q = c a q = \frac{c}{a} q = a c q = − 3 q = -3 q = − 3 v = d a v = \frac{d}{a} v = a d v = − 3 3 v = - \frac{\sqrt{3}}{3} v = − 3 3 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 = − 3 x_{1} + x_{2} + x_{3} = - \sqrt{3} x 1 + x 2 + x 3 = − 3 x 1 x 2 + x 1 x 3 + x 2 x 3 = − 3 x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = -3 x 1 x 2 + x 1 x 3 + x 2 x 3 = − 3 x 1 x 2 x 3 = − 3 3 x_{1} x_{2} x_{3} = - \frac{\sqrt{3}}{3} x 1 x 2 x 3 = − 3 3
/ ___ /pi\ \ ___ /pi\
___ | \/ 3 *sin|--| | \/ 3 *cos|--|
/pi\ / 1 \ \/ 3 | / 1 \ \9 / /pi\| \9 /
x1 = - sin|--| - 4*re|------------------------------------| - ----- + I*|- 4*im|------------------------------------| + ------------- + cos|--|| + -------------
\9 / |/ ___\ _________________| 3 | |/ ___\ _________________| 3 \9 /| 3
|| 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | |
||- - - -------|*\/ 12*\/ 3 + 36*I | | ||- - - -------|*\/ 12*\/ 3 + 36*I | |
\\ 2 2 / / \ \\ 2 2 / / /
x 1 = − 3 3 − sin ( π 9 ) − 4 re ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) + 3 cos ( π 9 ) 3 + i ( − 4 im ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) + 3 sin ( π 9 ) 3 + cos ( π 9 ) ) x_{1} = - \frac{\sqrt{3}}{3} - \sin{\left(\frac{\pi}{9} \right)} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{\sqrt{3} \cos{\left(\frac{\pi}{9} \right)}}{3} + i \left(- 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} + \cos{\left(\frac{\pi}{9} \right)}\right) x 1 = − 3 3 − sin ( 9 π ) − 4 re ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 + 3 3 cos ( 9 π ) + i − 4 im ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 + 3 3 sin ( 9 π ) + cos ( 9 π )
/ ___ /pi\\ ___ /pi\
___ | \/ 3 *sin|--|| \/ 3 *cos|--|
/ 1 \ \/ 3 | /pi\ / 1 \ \9 /| \9 / /pi\
x2 = - 4*re|------------------------------------| - ----- + I*|- cos|--| - 4*im|------------------------------------| + -------------| + ------------- + sin|--|
|/ ___\ _________________| 3 | \9 / |/ ___\ _________________| 3 | 3 \9 /
|| 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | |
||- - + -------|*\/ 12*\/ 3 + 36*I | | ||- - + -------|*\/ 12*\/ 3 + 36*I | |
\\ 2 2 / / \ \\ 2 2 / / /
x 2 = − 3 3 + sin ( π 9 ) + 3 cos ( π 9 ) 3 − 4 re ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) + i ( − cos ( π 9 ) + 3 sin ( π 9 ) 3 − 4 im ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) ) x_{2} = - \frac{\sqrt{3}}{3} + \sin{\left(\frac{\pi}{9} \right)} + \frac{\sqrt{3} \cos{\left(\frac{\pi}{9} \right)}}{3} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + i \left(- \cos{\left(\frac{\pi}{9} \right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} - 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)}\right) x 2 = − 3 3 + sin ( 9 π ) + 3 3 cos ( 9 π ) − 4 re ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1 + i − cos ( 9 π ) + 3 3 sin ( 9 π ) − 4 im ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1
_________________
___ 3 / ___
4 \/ 3 \/ 12*\/ 3 + 36*I
x3 = - -------------------- - ----- - --------------------
_________________ 3 3
3 / ___
\/ 12*\/ 3 + 36*I
x 3 = − 3 3 − 12 3 + 36 i 3 3 − 4 12 3 + 36 i 3 x_{3} = - \frac{\sqrt{3}}{3} - \frac{\sqrt[3]{12 \sqrt{3} + 36 i}}{3} - \frac{4}{\sqrt[3]{12 \sqrt{3} + 36 i}} x 3 = − 3 3 − 3 3 12 3 + 36 i − 3 12 3 + 36 i 4
x3 = -sqrt(3)/3 - (12*sqrt(3) + 36*i)^(1/3)/3 - 4/(12*sqrt(3) + 36*i)^(1/3)
Suma y producto de raíces
[src]
/ ___ /pi\ \ ___ /pi\ / ___ /pi\\ ___ /pi\ _________________
___ | \/ 3 *sin|--| | \/ 3 *cos|--| ___ | \/ 3 *sin|--|| \/ 3 *cos|--| ___ 3 / ___
/pi\ / 1 \ \/ 3 | / 1 \ \9 / /pi\| \9 / / 1 \ \/ 3 | /pi\ / 1 \ \9 /| \9 / /pi\ 4 \/ 3 \/ 12*\/ 3 + 36*I
- sin|--| - 4*re|------------------------------------| - ----- + I*|- 4*im|------------------------------------| + ------------- + cos|--|| + ------------- + - 4*re|------------------------------------| - ----- + I*|- cos|--| - 4*im|------------------------------------| + -------------| + ------------- + sin|--| + - -------------------- - ----- - --------------------
\9 / |/ ___\ _________________| 3 | |/ ___\ _________________| 3 \9 /| 3 |/ ___\ _________________| 3 | \9 / |/ ___\ _________________| 3 | 3 \9 / _________________ 3 3
|| 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | | 3 / ___
||- - - -------|*\/ 12*\/ 3 + 36*I | | ||- - - -------|*\/ 12*\/ 3 + 36*I | | ||- - + -------|*\/ 12*\/ 3 + 36*I | | ||- - + -------|*\/ 12*\/ 3 + 36*I | | \/ 12*\/ 3 + 36*I
\\ 2 2 / / \ \\ 2 2 / / / \\ 2 2 / / \ \\ 2 2 / / /
( ( − 3 3 + sin ( π 9 ) + 3 cos ( π 9 ) 3 − 4 re ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) + i ( − cos ( π 9 ) + 3 sin ( π 9 ) 3 − 4 im ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) ) ) + ( − 3 3 − sin ( π 9 ) − 4 re ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) + 3 cos ( π 9 ) 3 + i ( − 4 im ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) + 3 sin ( π 9 ) 3 + cos ( π 9 ) ) ) ) + ( − 3 3 − 12 3 + 36 i 3 3 − 4 12 3 + 36 i 3 ) \left(\left(- \frac{\sqrt{3}}{3} + \sin{\left(\frac{\pi}{9} \right)} + \frac{\sqrt{3} \cos{\left(\frac{\pi}{9} \right)}}{3} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + i \left(- \cos{\left(\frac{\pi}{9} \right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} - 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)}\right)\right) + \left(- \frac{\sqrt{3}}{3} - \sin{\left(\frac{\pi}{9} \right)} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{\sqrt{3} \cos{\left(\frac{\pi}{9} \right)}}{3} + i \left(- 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} + \cos{\left(\frac{\pi}{9} \right)}\right)\right)\right) + \left(- \frac{\sqrt{3}}{3} - \frac{\sqrt[3]{12 \sqrt{3} + 36 i}}{3} - \frac{4}{\sqrt[3]{12 \sqrt{3} + 36 i}}\right) − 3 3 + sin ( 9 π ) + 3 3 cos ( 9 π ) − 4 re ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1 + i − cos ( 9 π ) + 3 3 sin ( 9 π ) − 4 im ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1 + − 3 3 − sin ( 9 π ) − 4 re ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 + 3 3 cos ( 9 π ) + i − 4 im ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 + 3 3 sin ( 9 π ) + cos ( 9 π ) + ( − 3 3 − 3 3 12 3 + 36 i − 3 12 3 + 36 i 4 )
_________________ / ___ /pi\\ / ___ /pi\ \ ___ /pi\
3 / ___ | \/ 3 *sin|--|| | \/ 3 *sin|--| | 2*\/ 3 *cos|--|
___ 4 / 1 \ / 1 \ \/ 12*\/ 3 + 36*I | /pi\ / 1 \ \9 /| | / 1 \ \9 / /pi\| \9 /
- \/ 3 - -------------------- - 4*re|------------------------------------| - 4*re|------------------------------------| - -------------------- + I*|- cos|--| - 4*im|------------------------------------| + -------------| + I*|- 4*im|------------------------------------| + ------------- + cos|--|| + ---------------
_________________ |/ ___\ _________________| |/ ___\ _________________| 3 | \9 / |/ ___\ _________________| 3 | | |/ ___\ _________________| 3 \9 /| 3
3 / ___ || 1 I*\/ 3 | 3 / ___ | || 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | | | || 1 I*\/ 3 | 3 / ___ | |
\/ 12*\/ 3 + 36*I ||- - + -------|*\/ 12*\/ 3 + 36*I | ||- - - -------|*\/ 12*\/ 3 + 36*I | | ||- - + -------|*\/ 12*\/ 3 + 36*I | | | ||- - - -------|*\/ 12*\/ 3 + 36*I | |
\\ 2 2 / / \\ 2 2 / / \ \\ 2 2 / / / \ \\ 2 2 / / /
− 3 − 4 re ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) − 4 re ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) + 2 3 cos ( π 9 ) 3 − 12 3 + 36 i 3 3 + i ( − 4 im ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) + 3 sin ( π 9 ) 3 + cos ( π 9 ) ) + i ( − cos ( π 9 ) + 3 sin ( π 9 ) 3 − 4 im ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) ) − 4 12 3 + 36 i 3 - \sqrt{3} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{2 \sqrt{3} \cos{\left(\frac{\pi}{9} \right)}}{3} - \frac{\sqrt[3]{12 \sqrt{3} + 36 i}}{3} + i \left(- 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} + \cos{\left(\frac{\pi}{9} \right)}\right) + i \left(- \cos{\left(\frac{\pi}{9} \right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} - 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)}\right) - \frac{4}{\sqrt[3]{12 \sqrt{3} + 36 i}} − 3 − 4 re ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 − 4 re ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1 + 3 2 3 cos ( 9 π ) − 3 3 12 3 + 36 i + i − 4 im ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 + 3 3 sin ( 9 π ) + cos ( 9 π ) + i − cos ( 9 π ) + 3 3 sin ( 9 π ) − 4 im ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1 − 3 12 3 + 36 i 4
/ / ___ /pi\ \ ___ /pi\\ / / ___ /pi\\ ___ /pi\ \ / _________________\
| ___ | \/ 3 *sin|--| | \/ 3 *cos|--|| | ___ | \/ 3 *sin|--|| \/ 3 *cos|--| | | ___ 3 / ___ |
| /pi\ / 1 \ \/ 3 | / 1 \ \9 / /pi\| \9 /| | / 1 \ \/ 3 | /pi\ / 1 \ \9 /| \9 / /pi\| | 4 \/ 3 \/ 12*\/ 3 + 36*I |
|- sin|--| - 4*re|------------------------------------| - ----- + I*|- 4*im|------------------------------------| + ------------- + cos|--|| + -------------|*|- 4*re|------------------------------------| - ----- + I*|- cos|--| - 4*im|------------------------------------| + -------------| + ------------- + sin|--||*|- -------------------- - ----- - --------------------|
| \9 / |/ ___\ _________________| 3 | |/ ___\ _________________| 3 \9 /| 3 | | |/ ___\ _________________| 3 | \9 / |/ ___\ _________________| 3 | 3 \9 /| | _________________ 3 3 |
| || 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | | | | || 1 I*\/ 3 | 3 / ___ | | || 1 I*\/ 3 | 3 / ___ | | | | 3 / ___ |
| ||- - - -------|*\/ 12*\/ 3 + 36*I | | ||- - - -------|*\/ 12*\/ 3 + 36*I | | | | ||- - + -------|*\/ 12*\/ 3 + 36*I | | ||- - + -------|*\/ 12*\/ 3 + 36*I | | | \ \/ 12*\/ 3 + 36*I /
\ \\ 2 2 / / \ \\ 2 2 / / / / \ \\ 2 2 / / \ \\ 2 2 / / / /
( − 3 3 − sin ( π 9 ) − 4 re ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) + 3 cos ( π 9 ) 3 + i ( − 4 im ( 1 ( − 1 2 − 3 i 2 ) 12 3 + 36 i 3 ) + 3 sin ( π 9 ) 3 + cos ( π 9 ) ) ) ( − 3 3 + sin ( π 9 ) + 3 cos ( π 9 ) 3 − 4 re ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) + i ( − cos ( π 9 ) + 3 sin ( π 9 ) 3 − 4 im ( 1 ( − 1 2 + 3 i 2 ) 12 3 + 36 i 3 ) ) ) ( − 3 3 − 12 3 + 36 i 3 3 − 4 12 3 + 36 i 3 ) \left(- \frac{\sqrt{3}}{3} - \sin{\left(\frac{\pi}{9} \right)} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{\sqrt{3} \cos{\left(\frac{\pi}{9} \right)}}{3} + i \left(- 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} + \cos{\left(\frac{\pi}{9} \right)}\right)\right) \left(- \frac{\sqrt{3}}{3} + \sin{\left(\frac{\pi}{9} \right)} + \frac{\sqrt{3} \cos{\left(\frac{\pi}{9} \right)}}{3} - 4 \operatorname{re}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)} + i \left(- \cos{\left(\frac{\pi}{9} \right)} + \frac{\sqrt{3} \sin{\left(\frac{\pi}{9} \right)}}{3} - 4 \operatorname{im}{\left(\frac{1}{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{12 \sqrt{3} + 36 i}}\right)}\right)\right) \left(- \frac{\sqrt{3}}{3} - \frac{\sqrt[3]{12 \sqrt{3} + 36 i}}{3} - \frac{4}{\sqrt[3]{12 \sqrt{3} + 36 i}}\right) − 3 3 − sin ( 9 π ) − 4 re ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 + 3 3 cos ( 9 π ) + i − 4 im ( − 2 1 − 2 3 i ) 3 12 3 + 36 i 1 + 3 3 sin ( 9 π ) + cos ( 9 π ) − 3 3 + sin ( 9 π ) + 3 3 cos ( 9 π ) − 4 re ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1 + i − cos ( 9 π ) + 3 3 sin ( 9 π ) − 4 im ( − 2 1 + 2 3 i ) 3 12 3 + 36 i 1 ( − 3 3 − 3 3 12 3 + 36 i − 3 12 3 + 36 i 4 )
/ _________________ / _________________\\
3 ____ | 3 / ___ | ___ 3 / ___ || / /2*pi\ /pi\\
\/ 18 *\12 + \/ 12*\/ 3 + 36*I *\\/ 3 + \/ 12*\/ 3 + 36*I //*|9 - 24*cos|----| + 12*cos|--||
\ \ 9 / \9 //
-------------------------------------------------------------------------------------------------
_____________
3 / ___
162*\/ \/ 3 + 3*I
18 3 ( 12 + ( 3 + 12 3 + 36 i 3 ) 12 3 + 36 i 3 ) ( − 24 cos ( 2 π 9 ) + 9 + 12 cos ( π 9 ) ) 162 3 + 3 i 3 \frac{\sqrt[3]{18} \left(12 + \left(\sqrt{3} + \sqrt[3]{12 \sqrt{3} + 36 i}\right) \sqrt[3]{12 \sqrt{3} + 36 i}\right) \left(- 24 \cos{\left(\frac{2 \pi}{9} \right)} + 9 + 12 \cos{\left(\frac{\pi}{9} \right)}\right)}{162 \sqrt[3]{\sqrt{3} + 3 i}} 162 3 3 + 3 i 3 18 ( 12 + ( 3 + 3 12 3 + 36 i ) 3 12 3 + 36 i ) ( − 24 cos ( 9 2 π ) + 9 + 12 cos ( 9 π ) )
18^(1/3)*(12 + (12*sqrt(3) + 36*i)^(1/3)*(sqrt(3) + (12*sqrt(3) + 36*i)^(1/3)))*(9 - 24*cos(2*pi/9) + 12*cos(pi/9))/(162*(sqrt(3) + 3*i)^(1/3))