Rem equazioni logaritmiche
ListBox1.AddItem (" log(x^2-6) = log (5x+8) ")
ListBox1.AddItem (" per (x^2-6) >0 e (5x+8) > 0 ")
ListBox1.AddItem ("(x^2-6) = (5x+8)")
ListBox1.AddItem ("x^2 -5x -14 = 0")
ListBox1.AddItem (" radici : x1= -2 ; x2 = 7 ")
ListBox1.AddItem (" escludere x=-2 per condizione validità ")
x = 7
y1 = x ^ 2 - 6
y2 = 5 * x + 8
ListBox1.AddItem ("per x = " & 7 & " y1= " & y1 & " = y2 : " & y2 & " valido")
ListBox1.AddItem ("-----------------------------------------------")
For x = -5 To 10
y1 = x ^ 2 - 6
y2 = 5 * x + 8
If y1 > 0 And y2 > 0 And y1 = y2 Then
y = x ^ 2 - 5 * x - 14
ListBox1.AddItem (y1 & " = " & y2)
ListBox1.AddItem ("x = " & x & " y = " & y)
Else
ListBox1.AddItem (x & " non valido")
End If
Next x
End Sub
Private Sub CommandButton2_Click()
Rem esempio2
ListBox1.AddItem ("1/2*log(3x+5) + 1/2*log(x) = 1 ")
ListBox1.AddItem ("con (3x+5)> 0 e (x)>0 ")
ListBox1.AddItem ("log(sqr(3x+5)) + log(sqr(x))= log(10) ")
ListBox1.AddItem ("log(sqr(x(3x+5))= log(10) ")
ListBox1.AddItem ("sqr(x(3x+5)) = 10 ")
ListBox1.AddItem ("x(3x+5)=100 ")
ListBox1.AddItem ("3x^2+5x-100=0 ")
ListBox1.AddItem ("con radici x1= 5 ; x2 = -20/3 (da escludere) ")
ListBox1.AddItem ("---------------------------------------- ")
x = 5
y = 0.5 * (Log(3 * x + 5) / Log(10)) + 0.5 * (Log(x) / Log(10))
ListBox1.AddItem ("con x=5 :" & " soluzione y = " & y)
ListBox1.AddItem ("**********************************")
For x = -5 To 10
y1 = (3 * x + 5)
y2 = x
If y1 > 0 And y2 > 0 And (3 * x ^ 2 + 5 * x - 100 = 0) Then
y = 0.5 * (Log(3 * x + 5) / Log(10)) + 0.5 * (Log(x) / Log(10))
ListBox1.AddItem ("x = " & x & " y = " & y)
Else
ListBox1.AddItem (x & " non valido")
End If
Next x
End Sub
Private Sub CommandButton6_Click()
ListBox1.Clear
End Sub
