Cubic power of Cos (x+2x)(Cosx)

=(Sin2xCosx+Cos2xSinx)(Sinx) to the third power+

Cubic power of (Cos2xCosx-Sin2xSinx)(Cosx)

= (2 sinxcosxcosx+cos2xsinx) (sinx) to the third power+

The cubic power of (Cos2xCosx-2SinxCosxSinx)(Cosx)

=2Sinx quartic cosine squared +Cos2xSinx quartic+

Cos2xCosx quartic -2Sinx squared Cosx quartic

=2Sinx quartic cosine squared +Cos2x(Sinx quartic+

Cosx fourth power) -2Sinx square Cosx fourth power

=2Sinx squared Cosx squared (Sinx squared -Cosx squared)+

Cos2x(Sinx four times +Cosx four times)

=Cos2x(Sinx fourth power -2Sinx square Cosx square +Cosx fourth power)

=Cos2x(Sinx square -Cosx square) square brackets

= the square of =Cos2xCos2x

=Cos2x) to the third power