Question

Помогите номер 492 решить.

Answer 1

a)sinπ/33*cosπ/33*cos2π/22*cos4π/33*cos8π/33*cos16π/33/sinπ/33=
=sin2π/33*cos2π/22*cos4π/33*cos8π/33*cos16π/33/(2sinπ/33)=
=sin4π/33*cos4π/33*cos8π/33*cos16π/33/(4sinπ/33)=
=sin8π/33*cos8π/33*cos16π/33/(8sinπ/33)=sin16π/33*cos16π/33/(16sinπ/33)=
=sin32π/33/(32sinπ/33)=sin(π-π/33)/32sinπ/33=(sinπ/33)/32sinπ/33=1/32
b)cosπ/7cos4π/7cos(π-2π/7)=-cosπ/7cos2π/7cos4π/7=
=(-sinπ/7cosπ/7cos2π/7cos4π/7)/(sinπ/7)=(-sin2π/7cos2π/7cos4π/7)/(2sinπ/7)=
=(-sin4π/7cos4π/7)/(4sinπ/7)=(-sin8π/7)/(8sinπ/7)=(-sinπ/7)/(8sinπ/7)=-1/8