як спростити за допомогою формул зведення: y=-2 sin (П/2 - 3x)=???

Вот: sin (П/2 - 3x)=cos3x.

вот тебе скриптик, он поможет:

Public Sub RisPrm1()

''''' '''''
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''' ////?ENOAI I?AAO? NOAI?EO//// '''
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''''' ?eniaaiea eiioo?a noai?ee + oieioieoaeu - i?aaue i?iai '''''
sPrm1(0) = Npt1(0) - (Zpr / 2): sPrm1(1) = Npt1(1):
sPrm1(2) = sPrm1(0): sPrm1(3) = Npt1(1) + Hpr:
sPrm1(4) = Npt1(0) + Ots1: sPrm1(5) = sPrm1(3):
sPrm1(6) = sPrm1(4): sPrm1(7) = sPrm1(1)
Set Prm1 = ThisDrawing.ModelSpace.AddLightWeightPolyline(sPrm1)
Prm1.Closed = True
'Prm1.Linetype = "K5LT_DASHED_REINFORCED"
Prm1.Lineweight = acLnWt018
'''?eniaaiea eiioo?a noai?ee
sPrm2(0) = sPrm1(0) + Zpr: sPrm2(1) = sPrm1(1) + Zpr:
sPrm2(2) = sPrm1(2) + Zpr: sPrm2(3) = sPrm1(3) - Zpr:
sPrm2(4) = sPrm1(4) - Zpr: sPrm2(5) = sPrm1(3) - Zpr:
sPrm2(6) = sPrm1(6) - Zpr: sPrm2(7) = sPrm1(7) + Zpr
Set Prm2 = ThisDrawing.ModelSpace.AddLightWeightPolyline(sPrm2)
Prm2.Closed = True
Prm2.Linetype = "K5LT_DASHED_REINFORCED"
Prm2.Lineweight = acLnWt018
''' ?eniaaiea aioo?aiiae eeiee oaaeea?a
sPrm3(0) = sPrm2(0) + Pshv: sPrm3(1) = sPrm2(1) + Pshv:
sPrm3(2) = sPrm2(2) + Pshv: sPrm3(3) = sPrm2(3) - Pshv:
sPrm3(4) = sPrm2(4) - Pshv: sPrm3(5) = sPrm2(3) - Pshv:
sPrm3(6) = sPrm2(6) - Pshv: sPrm3(7) = sPrm2(7) + Pshv
Set Prm3 = ThisDrawing.ModelSpace.AddLightWeightPolyline(sPrm3)
Prm3.Closed = True
Prm3.Linetype = "K5LT_BASIC"
Prm3.Lineweight = acLnWt060
Call col.SetRGB(0, 0, 255)
Prm3.TrueColor = col
''' ?eniaaiea aioo?aiaae eeiee oieioieoaey
sPrm4(0) = sPrm2(0) + Nhl: sPrm4(1) = sPrm2(1) + Nhl:
sPrm4(2) = sPrm2(2) + Nhl: sPrm4(3) = sPrm2(3) - Nhl:
sPrm4(4) = sPrm2(4) - Nhl: sPrm4(5) = sPrm2(3) - Nhl:
sPrm4(6) = sPrm2(6) - Nhl: sPrm4(7) = sPrm2(7) + Nhl
Set Prm4 = ThisDrawing.ModelSpace.AddLightWeightPolyline(sPrm4)
Prm4.Closed = True
Prm4.Linetype = "K5LT_BASIC"
Prm4.Lineweight = acLnWt018
Prm4.TrueColor = col
'''?eniaaiea ia?o?iie eeiee oieioieoaey
sPrm5(0) = sPrm1(0) - Nhl: sPrm5(1) = sPrm1(1) - Nhl:
sPrm5(2) = sPrm1(2) - Nhl: sPrm5(3) = sPrm1(3) + Nhl:
sPrm5(4) = sPrm1(4) + Nhl: sPrm5(5) = sPrm1(3) + Nhl:
sPrm5(6) = sPrm1(6) + Nhl: sPrm5(7) = sPrm1(7) - Nhl
Set Prm5 = ThisDrawing.ModelSpace.AddLightWeightPolyline(sPrm5)
Prm5.Closed = True
Prm5.Linetype = "K5LT_BASIC"
Prm5.Lineweight = acLnWt060
Prm5.TrueColor = col
'''Aa?oeeaeuiay inaaa
Tch1(0) = Npt1(0): Tch1(1) = Npt1(1) - 0.15 * Hpr - Val(TextBox4.Text): Tch1(2) = 0#
Tch2(0) = Npt1(0): Tch2(1) = Npt1(1) + 1.15 * Hpr + Val(TextBox4.Text): Tch2(2) = 0#
Set lineOS1 = ThisDrawing.ModelSpace.AddLine(Tch1, Tch2)
lineOS1.Linetype = "K5LT18"
Call col.SetRGB(255, 128, 0)
lineOS1.TrueColor = col
'''Ai?eciioaeuiay inaaay
Tch3(1) = Npt1(1) + Hpr / 2: Tch3(0) = Npt1(0) - 2 * Pshv - Zpr: Tch3(2) = 0#
Tch4(1) = Npt1(1) + Hpr / 2: Tch4(0) = Npt1(0) + 2 * Pshv + Zpr: Tch4(2) = 0#
Set lineOS2 = ThisDrawing.ModelSpace.AddLine(Tch3, Tch4)
lineOS2.Linetype = "K5LT18"
Call col.SetRGB(255, 128, 0)
lineOS2.TrueColor = col
'''
If Mst <> 1 Then
Prm1.ScaleEntity Npt1, 1 / Mst
Prm2.ScaleEntity Npt1, 1 / Mst
Prm3.ScaleEntity Npt1, 1 / Mst
Prm4.ScaleEntity Npt1, 1 / Mst
Prm5.ScaleEntity Npt1, 1 / Mst
lineOS1.ScaleEntity Npt1, 1 / Mst
lineOS2.ScaleEntity Npt1, 1 / Mst
End If
Prm1.Update: Prm2.Update: Prm3.Update: Prm4.Update: Prm5.Update: lineOS1.Update: lineOS1.Update