1. Найдите: (a) sin α, если cos α = 1/4; (b) tg α, если cos α = √3/2;

(a) sin α = ±√(1 - cos²α) = ±√(1 - (1/4)²) = ±√(15/16) = ±√15/4. (b) tg α = sin α / cos α, при cos α = √3/2, sin α = ±√(1 - cos²α) = ±√(1 - (√3/2)²) = ±√(1/4) = ±1/2, tg α = ±(1/2)/(√3/2) = ±1/√3.