Question

найти sin a, tg a, ctg a, если cos a = -(8/17), п/2 < a < п

Answer 1

1.sin=√1-cos²a=√1-64/289=√225/289=15/17
2.tg=sina/cosa=15/17/(-8/17)=-15/8=-1 7/8
3.ctga=cosa/sina=(-8/17)/(15/17)=-8/15