Разложите выражение на множители. cos74+cos62+cos50

cos74+cos62+cos50= (cos74+cos50)+cos62=2cos((74+50)/2)*cos((74-50)/2)+cos62=2cos62*cos12+cos62=cos62(2cos12+1)=2*cos62(cos12+1/2)=2*cos62(cos12+cos60)=2*cos62*2*cos((60+12)/2)*cos((60-12)/2)=4*cos62*cos36*cos24