Решить \/2*sin7П/8*cos7П/8

Question

Решить
\/2*sin7П/8*cos7П/8

Answer 1

√2sin(7π/8)cos(7π/8)=(√2√2sin(7π/8)cos(7π/8))/√2=
=2sin(7π/8)cos(7π/8)/√2=(sin2(7π/8))/√2=(sin(7π/4))/√2=
=(-sin(π/4))/√2=((-√2)/2)/√2)=-1/2



(2sinxcosx=sin2x)