# RHS = cos6x-2cos4x-cos2x + 2 #
# = cos6x-cos2x + 2 (1-cos4x) #
# = - 2sin ((6X + 2X) / 2) * الخطيئة ((6X-2X) / 2) + 2 * 2sin ^ 2 (2X) #
# = 4sin ^ 2 (2X) -2sin4x * sin2x = 4sin ^ 2 (2X) -2 * 2 * * sin2x cos2x * sin2x #
# = 4sin ^ 2 (2X) -4sin ^ 2 (2X) * cos2x #
# = 4sin ^ 2 (2X) 1-cos2x #
# = 4 * (* 2sinx cosx) ^ 2 * 2sin ^ 2X #
# = 4 * 4sin ^ 2X * جتا ^ 2X * 2sin ^ 2X = 32sin ^ 4X * جتا ^ 2X = LHS #