§ 26: 26.3 (1-2)

26.3 Перетворіть у добуток вираз:

1) 2(12 – cosα) = 2(cosπ3 – cosα) = 2 • 2 • sinπ3+ α2 sinα- π32 = 4sin(α2 + π6)sin(α2 + π6);

2) (32 + cosα) = 2(cosπ6 + cosα) = 4cosπ6+ α2 cosπ6- α2 = 4cos(π12 + α6)sin(π12 + α2);

3) 2(12 – sinα) = 2(sinπ4 – sinα) = 2 • 2sin(π8 – α2)sin(π8 + α2) = 22sin(π8 – α2) sin(π8 + α2).

4) 3 + ctgα = ctg30° + ctgα = sin(30°+ α)sin30° • sinα = 2sin(30°+ α)sinα.