Timeline for roots of a fourth degree polynomial function (Vieta)
Current License: CC BY-SA 4.0
12 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 20, 2022 at 12:38 | comment | added | Steven Landsburg | The semicolon suppressed the output. Try typing x1 (or x2 or x3 or x4) after the program runs. | |
| Apr 20, 2022 at 9:24 | comment | added | toni_iva | I writed sol=Solve[x^4 + (a+b+c+d-2) x^3 + (ab+ac+ad+bc+bd+cd-2b-2c-a-d) x^2 +(abc+abd+acd+bcd-ab-ac-ad-2bc-bd-cd-a-d+b+c)x + abcd-abc-bcd-ad+bc == 0, x];x1=x/.sol[[1]];x2=x/.sol[[2]];x3=x/.sol[[3]];x4=x/.sol[[4]]; but get no Output. :( | |
| Apr 19, 2022 at 17:49 | comment | added | Carlo Beenakker | sol = Solve[.....==0,x];x1=x/.sol[[1]];x2=x/.sol[[2];x3=x/.sol[[3];x4=x/.sol[[4]; then the four variables x1,x2,x3,x4 contain the four solutions; x1 and x2 are complex, x3 and x4 are real. | |
| Apr 19, 2022 at 17:47 | comment | added | toni_iva | Do you know how i can see the four solutions? | |
| Apr 19, 2022 at 17:21 | comment | added | toni_iva | Thank you, but I only see one solution? | |
| Apr 19, 2022 at 17:02 | comment | added | Carlo Beenakker | Solve[x^4 + (a + b + c + d - 2) x^3 + (a b + a c + a d + b c + b d + c d - 2 b - 2 c - a - d) x^2 + (a b c + a b d + a c d + b c d - a b - a c - a d - 2 b c - b d - c d - a - d + b + c) x + a b c d - a b c - b c d - a d + b c == 0, x] | |
| Apr 19, 2022 at 16:47 | comment | added | toni_iva | Do you solve it with ‚Roots‘ or with ‚Reduce‘? | |
| Apr 19, 2022 at 16:36 | comment | added | toni_iva | I just tried with Mathematica, but I always get an error. :( | |
| Apr 19, 2022 at 16:04 | comment | added | Carlo Beenakker | Mathematica will readily give you the general expression for all four roots (two real, two complex); the expression for each root is about 250 lines long, what could you possibly do with it? | |
| Apr 19, 2022 at 15:39 | comment | added | toni_iva | I need the general expression. How can i obtain it? | |
| Apr 19, 2022 at 15:31 | comment | added | toni_iva | Thank you for the comment. How do you know there are two real solutions? | |
| Apr 19, 2022 at 15:29 | history | answered | Carlo Beenakker | CC BY-SA 4.0 |