Question

преобразовать в произведение 1)cos40- cos20 Все меры градусные
2)sin20-cos40

Answer 1

$mathtt{1.cos(40)-cos(20)=2cos^2(20)-1-cos(20)=(cos(20)-1)*(cos(20)+0.5)}\mathtt{2.sin(20)-cos(40)=sin(20)-(1-2sin^2(20))=2sin^2(20)-1+sin(20)=}\mathtt{=(sin(20)-1)*(sin(20)+0.5)}$