Question

Найти значение выражения
а)sin151ºcos164º+cos151ºsin164º
б)cos2Пи/3 cosПи/2+sin2Пи/3 sinПи/2

Answer 1

а) sin151° cos164° +cos151° sin164° = sin(151° + 164°) = sin 315° = -√2/2

б) cos(2π/3) · cos(π/2) + sin(2π/3) · sin(π/2) = сos((2π/3)-(π/2)) = cos (π/6) = √3/2