4.10. sin α = −12/13, 3π/2 < α < 2π.

В IV четверти cos α > 0.

\(\cos\alpha=\sqrt{1-\frac{144}{169}}=\frac{5}{13}\).

\( g\alpha=-\frac{12}{5}\), \(\ctg\alpha=-\frac{5}{12}\).

Ответ: cos α = 5/13; tg α = −12/5; ctg α = −5/12.