1. Вычислить, отметив угол на окружности: а) cos510°; б) cos(-11π/3); в) tg(11π/6)

а) cos510° = cos(510° - 360°) = cos150° = cos(180° - 30°) = -cos30° = **-√3/2** б) cos(-11π/3) = cos(11π/3) = cos(12π/3 - π/3) = cos(4π - π/3) = cos(-π/3) = cos(π/3) = **1/2** в) tg(11π/6) = tg(12π/6 - π/6) = tg(2π - π/6) = tg(-π/6) = -tg(π/6) = **-√3/3**