помогите решить)))) 14sin120*cos150=

Question

помогите решить))))

14sin120*cos150=

Answer 1

14*sin(120°)*cos(150°)=14*sin(90°+30°)*cos(90°+60°)=

=14*cos(30°)*(-sin(60°)=-14*(sqrt(3)/2)*sgrt(3)/2=-14*3/4=-10,5