Упростите выражение: sin(2π/7 - c)×cos(3π/14+c) + cos(2π/7 - c)× sin(3π/14+c)

Question

Упростите выражение: sin(2π/7 - c)×cos(3π/14+c) + cos(2π/7 - c)× sin(3π/14+c)

Answer 1

=sin(2П/7-c+3П/14+c)=sin(4П/14+3П/14)=sin(П/2)=1