解一元四次方程vb程序.doc

费拉里公式:一元四次方程 令，则 ，此方程是以下两个一元二次方程的解：；，其中；，。是一元三次方程的任一实根。盛金公式:一元三次方程 ， 重根判别式：；，总判别式：。当时，盛金公式：。 当时，盛金公式：；, 其中， 。当时，盛金公式：；， 其中， 。当时，盛金公式：；， 其中， （，)。一元四次方程先化成一元三次方程和两个一元二次方程，再根据费拉里公式和盛金公式求出四个根。Private Sub Command1_Click() Open C:abc + Combo2.Text For Input As #3 Input #3, dy, cy, by, ay Input #3, B1(0), B1(1), B1(2), B1(3), B1(4) Input #3, B2(0), B2(1), B2(2), B2(3), B2(4) Input #3, B3(0), B3(1), B3(2), B3(3), B3(4) Input #3, B4(0), B4(1), B4(2), B4(3), B4(4) Close #3 WED = Val(Text2.Text) eh = B1(0) + B2(0) * WED + B3(0) * WED 2 + B4(0) * WED 3 dh = B1(1) + B2(1) * WED + B3(1) * WED 2 + B4(1) * WED 3 ch = B1(2) + B2(2) * WED + B3(2) * WED 2 + B4(2) * WED 3 bh = B1(3) + B2(3) * WED + B3(3) * WED 2 + B4(3) * WED 3 ah = B1(4) + B2(4) * WED + B3(4) * WED 2 + B4(4) * WED 3 If ah 0 Then xy3 = (-by + (Det) (1 / 2) / 2 * ay xy4 = (-by - (Det) (1 / 2) / 2 * ay Else: End If ay = 2 by = bh - Mq cy = 2 * (Yli - Nq / Mq) Det = by 2 - 4 * ay * cy If Det = 0 Then xy1 = -by / 2 * ay xy2 = xy1 Else: End If If Det 0 Then xy3 = (-by + (Det) (1 / 2) / 2 * ay xy4 = (-by - (Det) (1 / 2) / 2 * ay Else: End IfEnd SubPrivate Sub jiefangc() Dim tt As Double AA1 = by 2 - 3 * ay * cy BB1 = by * cy - 9 * ay * dy CC1 = cy 2 - 3 * by * dy CC1 = Format(CC1, 000.00000) Det = BB1 2 - 4 * AA1 * CC1 Text11.Text = AA1 Text12.Text = BB1 Text19.Text = CC1 Text21.Text = Det If AA1 = 0 And BB1 = 0 Then xy1 = -by / (3 * ay) xy2 = -cy / by xy3 = -3 * dy / cy Else: End If If Det 0 Then Yq1 = AA1 * by + 3 * ay * (-BB1 + (BB1 2 - 4 * AA1 * CC1) (1 / 2) / 2 Yq2 = AA1 * by + 3 * ay * (-BB1 - (BB1 2 - 4 * AA1 * CC1) (1 / 2) / 2 If Yq1 0 And Yq2 0 Then xy1 = (-by - (-(-Yq1) (1 / 3) - (-(-Yq2) (1 / 3) / (3 * ay) Else: End If If Yy1 0 Then xy1 = (-by - (-(-Yq1) (1 / 3) - (Yq2) (1 / 3) / (3 * ay) Else: End If If Yq2 0 Then xy1 = (-by - Yq1 (1 / 3) - (-(-Yq2) (1 / 3) / (3 * ay) Else: End If xy2 = 0 xy3 = 0 Else: End If If Det = 0 Then KK = BB1 / AA1 xy1 = -by / ay + KK xy2 = -KK / 2 xy3 = xy2 Else: End If If Det 0 Then tt = (2 * AA1 * by - 3 * ay * BB1) / (2 * (AA1 3) (1 / 2) tt = Arccos(tt) xy1 = (-by - 2 * AA1 (1 / 2) * Cos(tt / 3) / (3 * ay) xy2 = (-by + AA1 (1 / 2) * (Cos(tt / 3) + 3 (1 / 2) * Sin(t