Question

Найдите tga, если sina = -5/13 и 1,5π<а<2,5π

Answer 1

sina=-5/13 a-4ч⇒cosa>0
cosa=√(1-sin²a)=√(1-25/169)=√(144/169)=12/13
tga=sina/cosa=-5/13:12/13=-5/13*13/12=-5/12