VB常用数值算法集 内含有解线性代数方程组

				Sub ZBRAC(X1, X2, SUCCES)
				    FACTOR = 1.6
				    NTRY = 50
				    If X1 = X2 Then Print "you have to guess an initial range"
				    F1 = FUN(X1)
				    F2 = FUN(X2)
				    SUCCES = True
				    For J = 1 To NTRY
				        If F1 * F2 < 0 Then Exit Sub
				        If Abs(F1) < Abs(F2) Then
				            X1 = X1 + FACTOR * (X1 - X2)
				            F1 = FUN(X1)
				        Else
				            X2 = X2 + FACTOR * (X2 - X1)
				            F2 = FUN(X2)
				        End If
				    Next J
				    SUCCES = False
				End Sub