Question

Найди значение выражения:
sin*π/21⋅cos*2π/7+cos*π/21⋅sin*2/π7

Answer 1

sin*π/21⋅cos*2π/7+cos*π/21⋅sin*2/π7=sin(π/21+2π/7)=sin(π/21+6π/21)= sin(π/3)=√3/2