x^3-3*x^2-1=0 la ecuación
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Solución
Teorema de Cardano-Vieta
es ecuación cúbica reducida
px2+qx+v+x3=0donde
p=abp=−3q=acq=0v=adv=−1Fórmulas de Cardano-Vieta
x1+x2+x3=−px1x2+x1x3+x2x3=qx1x2x3=vx1+x2+x3=3x1x2+x1x3+x2x3=0x1x2x3=−1
Gráfica
___________ / ___________\
/ ___ | / ___ |
/ 3 \/ 5 | ___ / 3 \/ 5 |
3 / - + ----- | ___ \/ 3 *3 / - + ----- |
1 \/ 2 2 | \/ 3 \/ 2 2 |
x1 = 1 - ------------------ - ---------------- + I*|------------------ - ----------------------|
___________ 2 | ___________ 2 |
/ ___ | / ___ |
/ 3 \/ 5 | / 3 \/ 5 |
2*3 / - + ----- |2*3 / - + ----- |
\/ 2 2 \ \/ 2 2 /
x1=−2325+23−2325+231+1+i−23325+23+2325+233
___________ / ___________ \
/ ___ | / ___ |
/ 3 \/ 5 | ___ / 3 \/ 5 |
3 / - + ----- |\/ 3 *3 / - + ----- ___ |
1 \/ 2 2 | \/ 2 2 \/ 3 |
x2 = 1 - ------------------ - ---------------- + I*|---------------------- - ------------------|
___________ 2 | 2 ___________|
/ ___ | / ___ |
/ 3 \/ 5 | / 3 \/ 5 |
2*3 / - + ----- | 2*3 / - + ----- |
\/ 2 2 \ \/ 2 2 /
x2=−2325+23−2325+231+1+i−2325+233+23325+23
___________
/ ___
1 / 3 \/ 5
x3 = 1 + ---------------- + 3 / - + -----
___________ \/ 2 2
/ ___
/ 3 \/ 5
3 / - + -----
\/ 2 2
x3=325+231+1+325+23
x3 = (sqrt(5)/2 + 3/2)^(-1/3) + 1 + (sqrt(5)/2 + 3/2)^(1/3)
Suma y producto de raíces
[src]
___________ / ___________\ ___________ / ___________ \
/ ___ | / ___ | / ___ | / ___ |
/ 3 \/ 5 | ___ / 3 \/ 5 | / 3 \/ 5 | ___ / 3 \/ 5 | ___________
3 / - + ----- | ___ \/ 3 *3 / - + ----- | 3 / - + ----- |\/ 3 *3 / - + ----- ___ | / ___
1 \/ 2 2 | \/ 3 \/ 2 2 | 1 \/ 2 2 | \/ 2 2 \/ 3 | 1 / 3 \/ 5
1 - ------------------ - ---------------- + I*|------------------ - ----------------------| + 1 - ------------------ - ---------------- + I*|---------------------- - ------------------| + 1 + ---------------- + 3 / - + -----
___________ 2 | ___________ 2 | ___________ 2 | 2 ___________| ___________ \/ 2 2
/ ___ | / ___ | / ___ | / ___ | / ___
/ 3 \/ 5 | / 3 \/ 5 | / 3 \/ 5 | / 3 \/ 5 | / 3 \/ 5
2*3 / - + ----- |2*3 / - + ----- | 2*3 / - + ----- | 2*3 / - + ----- | 3 / - + -----
\/ 2 2 \ \/ 2 2 / \/ 2 2 \ \/ 2 2 / \/ 2 2
325+231+1+325+23+−2325+23−2325+231+1+i−23325+23+2325+233+−2325+23−2325+231+1+i−2325+233+23325+23
/ ___________\ / ___________ \
| / ___ | | / ___ |
| ___ / 3 \/ 5 | | ___ / 3 \/ 5 |
| ___ \/ 3 *3 / - + ----- | |\/ 3 *3 / - + ----- ___ |
| \/ 3 \/ 2 2 | | \/ 2 2 \/ 3 |
3 + I*|------------------ - ----------------------| + I*|---------------------- - ------------------|
| ___________ 2 | | 2 ___________|
| / ___ | | / ___ |
| / 3 \/ 5 | | / 3 \/ 5 |
|2*3 / - + ----- | | 2*3 / - + ----- |
\ \/ 2 2 / \ \/ 2 2 /
3+i−23325+23+2325+233+i−2325+233+23325+23
/ ___________ / ___________\\ / ___________ / ___________ \\
| / ___ | / ___ || | / ___ | / ___ ||
| / 3 \/ 5 | ___ / 3 \/ 5 || | / 3 \/ 5 | ___ / 3 \/ 5 || / ___________\
| 3 / - + ----- | ___ \/ 3 *3 / - + ----- || | 3 / - + ----- |\/ 3 *3 / - + ----- ___ || | / ___ |
| 1 \/ 2 2 | \/ 3 \/ 2 2 || | 1 \/ 2 2 | \/ 2 2 \/ 3 || | 1 / 3 \/ 5 |
|1 - ------------------ - ---------------- + I*|------------------ - ----------------------||*|1 - ------------------ - ---------------- + I*|---------------------- - ------------------||*|1 + ---------------- + 3 / - + ----- |
| ___________ 2 | ___________ 2 || | ___________ 2 | 2 ___________|| | ___________ \/ 2 2 |
| / ___ | / ___ || | / ___ | / ___ || | / ___ |
| / 3 \/ 5 | / 3 \/ 5 || | / 3 \/ 5 | / 3 \/ 5 || | / 3 \/ 5 |
| 2*3 / - + ----- |2*3 / - + ----- || | 2*3 / - + ----- | 2*3 / - + ----- || | 3 / - + ----- |
\ \/ 2 2 \ \/ 2 2 // \ \/ 2 2 \ \/ 2 2 // \ \/ 2 2 /
−2325+23−2325+231+1+i−2325+233+23325+23−2325+23−2325+231+1+i−23325+23+2325+233325+231+1+325+23
x1 = -0.0519017013677683 + 0.565235851677171*i
x2 = -0.0519017013677683 - 0.565235851677171*i