2*x^3-7*x^2+5*x-19=0 la ecuación
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Solución
Teorema de Cardano-Vieta
reescribamos la ecuación
(5x+(2x3−7x2))−19=0de
ax3+bx2+cx+d=0como ecuación cúbica reducida
x3+abx2+acx+ad=0x3−27x2+25x−219=0px2+qx+v+x3=0donde
p=abp=−27q=acq=25v=adv=−219Fórmulas de Cardano-Vieta
x1+x2+x3=−px1x2+x1x3+x2x3=qx1x2x3=vx1+x2+x3=27x1x2+x1x3+x2x3=25x1x2x3=−219
Gráfica
Suma y producto de raíces
[src]
__________________ / __________________ \ __________________ / __________________ \
/ ________ | / ________ | / ________ | / ________ |
/ 527 \/ 122673 | ___ / 527 \/ 122673 | / 527 \/ 122673 | ___ / 527 \/ 122673 | __________________
3 / --- + ---------- | \/ 3 *3 / --- + ---------- ___ | 3 / --- + ---------- |\/ 3 *3 / --- + ---------- ___ | / ________
7 19 \/ 108 72 | \/ 108 72 19*\/ 3 | 7 19 \/ 108 72 | \/ 108 72 19*\/ 3 | 7 / 527 \/ 122673 19
- - -------------------------- - ----------------------- + I*|- ----------------------------- + --------------------------| + - - -------------------------- - ----------------------- + I*|----------------------------- - --------------------------| + - + 3 / --- + ---------- + --------------------------
6 __________________ 2 | 2 __________________| 6 __________________ 2 | 2 __________________| 6 \/ 108 72 __________________
/ ________ | / ________ | / ________ | / ________ | / ________
/ 527 \/ 122673 | / 527 \/ 122673 | / 527 \/ 122673 | / 527 \/ 122673 | / 527 \/ 122673
72*3 / --- + ---------- | 72*3 / --- + ---------- | 72*3 / --- + ---------- | 72*3 / --- + ---------- | 36*3 / --- + ----------
\/ 108 72 \ \/ 108 72 / \/ 108 72 \ \/ 108 72 / \/ 108 72
36372122673+10852719+67+372122673+108527+−2372122673+108527−72372122673+10852719+67+i−23372122673+108527+72372122673+108527193+−2372122673+108527−72372122673+10852719+67+i−72372122673+108527193+23372122673+108527
/ __________________ \ / __________________ \
| / ________ | | / ________ |
| ___ / 527 \/ 122673 | | ___ / 527 \/ 122673 |
|\/ 3 *3 / --- + ---------- ___ | | \/ 3 *3 / --- + ---------- ___ |
7 | \/ 108 72 19*\/ 3 | | \/ 108 72 19*\/ 3 |
- + I*|----------------------------- - --------------------------| + I*|- ----------------------------- + --------------------------|
2 | 2 __________________| | 2 __________________|
| / ________ | | / ________ |
| / 527 \/ 122673 | | / 527 \/ 122673 |
| 72*3 / --- + ---------- | | 72*3 / --- + ---------- |
\ \/ 108 72 / \ \/ 108 72 /
27+i−23372122673+108527+72372122673+108527193+i−72372122673+108527193+23372122673+108527
/ __________________ / __________________ \\ / __________________ / __________________ \\
| / ________ | / ________ || | / ________ | / ________ ||
| / 527 \/ 122673 | ___ / 527 \/ 122673 || | / 527 \/ 122673 | ___ / 527 \/ 122673 || / __________________ \
| 3 / --- + ---------- | \/ 3 *3 / --- + ---------- ___ || | 3 / --- + ---------- |\/ 3 *3 / --- + ---------- ___ || | / ________ |
|7 19 \/ 108 72 | \/ 108 72 19*\/ 3 || |7 19 \/ 108 72 | \/ 108 72 19*\/ 3 || |7 / 527 \/ 122673 19 |
|- - -------------------------- - ----------------------- + I*|- ----------------------------- + --------------------------||*|- - -------------------------- - ----------------------- + I*|----------------------------- - --------------------------||*|- + 3 / --- + ---------- + --------------------------|
|6 __________________ 2 | 2 __________________|| |6 __________________ 2 | 2 __________________|| |6 \/ 108 72 __________________|
| / ________ | / ________ || | / ________ | / ________ || | / ________ |
| / 527 \/ 122673 | / 527 \/ 122673 || | / 527 \/ 122673 | / 527 \/ 122673 || | / 527 \/ 122673 |
| 72*3 / --- + ---------- | 72*3 / --- + ---------- || | 72*3 / --- + ---------- | 72*3 / --- + ---------- || | 36*3 / --- + ---------- |
\ \/ 108 72 \ \/ 108 72 // \ \/ 108 72 \ \/ 108 72 // \ \/ 108 72 /
−2372122673+108527−72372122673+10852719+67+i−72372122673+108527193+23372122673+108527−2372122673+108527−72372122673+10852719+67+i−23372122673+108527+72372122673+10852719336372122673+10852719+67+372122673+108527
__________________ / __________________ \
/ ________ | / ________ |
/ 527 \/ 122673 | ___ / 527 \/ 122673 |
3 / --- + ---------- | \/ 3 *3 / --- + ---------- ___ |
7 19 \/ 108 72 | \/ 108 72 19*\/ 3 |
x1 = - - -------------------------- - ----------------------- + I*|- ----------------------------- + --------------------------|
6 __________________ 2 | 2 __________________|
/ ________ | / ________ |
/ 527 \/ 122673 | / 527 \/ 122673 |
72*3 / --- + ---------- | 72*3 / --- + ---------- |
\/ 108 72 \ \/ 108 72 /
x1=−2372122673+108527−72372122673+10852719+67+i−23372122673+108527+72372122673+108527193
__________________ / __________________ \
/ ________ | / ________ |
/ 527 \/ 122673 | ___ / 527 \/ 122673 |
3 / --- + ---------- |\/ 3 *3 / --- + ---------- ___ |
7 19 \/ 108 72 | \/ 108 72 19*\/ 3 |
x2 = - - -------------------------- - ----------------------- + I*|----------------------------- - --------------------------|
6 __________________ 2 | 2 __________________|
/ ________ | / ________ |
/ 527 \/ 122673 | / 527 \/ 122673 |
72*3 / --- + ---------- | 72*3 / --- + ---------- |
\/ 108 72 \ \/ 108 72 /
x2=−2372122673+108527−72372122673+10852719+67+i−72372122673+108527193+23372122673+108527
__________________
/ ________
7 / 527 \/ 122673 19
x3 = - + 3 / --- + ---------- + --------------------------
6 \/ 108 72 __________________
/ ________
/ 527 \/ 122673
36*3 / --- + ----------
\/ 108 72
x3=36372122673+10852719+67+372122673+108527
x3 = 19/(36*(sqrt(122673)/72 + 527/108)^(1/3)) + 7/6 + (sqrt(122673)/72 + 527/108)^(1/3)
x1 = -0.0248341974384107 - 1.63575352487962*i
x3 = -0.0248341974384107 + 1.63575352487962*i
x3 = -0.0248341974384107 + 1.63575352487962*i