Quadratic Equation

[CoreyN]

What is the code for a program that will calculate the qudratic eqatuion! Your help will be greatly appreciated.

[thinktank]

I guess, you want the equation from known roots..

If a,b be the two roots

and S be their sum, P be their products...

X²-(S)X+P = 0

is the equation.

[CoreyN]

No, I am trying to make a program in visual basic that will calculate the quadratic equation and i can't get it to work. I was needing some help if anyone is able. Thanks again...

Corey

[Kaverin]

Do you mean solve a quadratic equation? If not, explain what you mean more clearly. If you're trying to solve one, you could use this if you wanted.

Public Function QuadraticFormula(ByVal a As Double, ByVal b As Double, ByVal c As Double, ByRef dblPosRoot As Double, ByRef dblNegRoot As Double) As Boolean
   Dim dblDescriminant As Double
   QuadraticFormula = False
   dblDescriminant = (b * b) - (4 * a * c)
   If dblDescriminant < 0 Then Exit Function
   dblPosRoot = (-b + Sqr(dblDescriminant)) / (2 * a)
   dblNegRoot = (-b - Sqr(dblDescriminant)) / (2 * a)
   QuadraticFormula = True
End Function
 
'to use it to solve ax² + bx + c = 0
Dim dblPosRoot As Double 'holds the "positive" root
Dim dblNegRoot As Double 'holds the "negative" root
If QuadraticFormula(a, b, c, dblPosRoot, dblNegRoot) Then
   Debug.Print "the roots are"; dblPosRoot; "and"; dblNegRoot
Else
   Debug.Print "the roots are imaginary"
End If