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+--- Thread: Calculating with complex numbers (/showthread.php?tid=586)
Calculating with complex numbers - Kernelpanic - 07-05-2022
This is from the QBasic Tech Reference book, and is intended to demonstrate math with complex numbers. I myself can't see through it anymore, but anyone who deals with mathematics can perhaps use it.
Code: (Select All)
'Loesung quadratischer Gleichungen S. 231, QBasic Referenz - 5. Juli 2022
Option _Explicit
Dim a, b, c, det As Double
Dim j As String
Do
Cls
Print "Geben Sie die Parameter a, b, c der Gleichung ax^2 + bx + c = 0 ein: "
Input "a = "; a: Input "b = "; b: Input "c = "; c
Print "Loesung: ";
If a = 0 Then
If b = 0 Then Print "alle Zahlen" Else Print "x = "; -c / b
Else det = b * b - 4 * a * c
If det >= 0 Then
Print "x1 = "; (-b + Sqr(det)) / 2 / a; "x2 = "; (-b - Sqr(det)) / 2 / a
Else
Print "x1 = "; b / 2 / a; "+"; Sqr(det) / 2 / a; "* i;";
Print " x2 = "; b / 2 / a; "-"; Sqr(det) / 2 / a; "* i"
End If
End If
Print
Input "Nochmal (J/N)", j
Loop Until UCase$(j) = "N"
EndRE: Calculating with complex numbers - BSpinoza - 07-06-2022
@Kernelpanic:
Your program only solves quadratic equations with real solutions (roots).
If you try to solve a quadratic equation with complex roots, you will get an error.
example:
x^4 - 4 x +7 = 0
This equation has two complex roots:
x_1 = 2 - sqr(3i)
x_2 = 2 + sqr(3i)
I have attached a program, which solves the roots of a polynomial up to degree 10.
It gives in the most cases all roots of a polynomial and uses the Lin-Bairstow-Method.
RE: Calculating with complex numbers - euklides - 07-06-2022
Very good program, Bruno !
RE: Calculating with complex numbers - Kernelpanic - 07-06-2022
(07-06-2022, 07:07 AM)BSpinoza Wrote: @Kernelpanic:
Your program only solves quadratic equations with real solutions (roots).
If you try to solve a quadratic equation with complex roots, you will get an error.
example:
x^4 - 4 x +7 = 0
This equation has two complex roots:
x_1 = 2 - sqr(3i)
x_2 = 2 + sqr(3i)
I have attached a program, which solves the roots of a polynomial up to degree 10.
It gives in the most cases all roots of a polynomial and uses the Lin-Bairstow-Method.
Excellent program, but unfortunately I have no idea anymore of the matter. I had to first look up again what a polynomial is.
I misunderstood something in the description, one should be able to solve all quadratic equations with it.
Rechnet man nicht mit reellen , sondern mit komplexen Zahlen, ist die Wurzel von -1 als i (imaginäreZahl) definiert. Die Darstellung einer komplexen Zahl ist dann Realteil + Imaginärteil. In diesem Kalkül können alle quadratischen Gleichungen gelöst werden.
RE: Calculating with complex numbers - bplus - 07-06-2022
Yah, Solves quadratics, no calculating complex numbers except if root of the quadratic given in standard form with a, b, c as real numbers because again no complex calculation of b^2-4*a*c eg b = -i ???
RE: Calculating with complex numbers - triggered - 07-07-2022
"Yah, Solves quadratics, no calculating complex numbers except if root of the quadratic given in standard form with a, b, c as real numbers because again no complex calculation of b^2-4*a*c eg b = -i ???"
Bplus is the only guy who can slowly turn a run-on sentence into a run-on question.