Question

Спасайте, срочно надо :с

Answer 1

Cosα = -12/13
a ∈ III ⇒ sinα < 0
sinα = - √(1-cos²α) = - √(1-144/169) = - √(25/169) = -5/13

tgα = sinα / cosα = -5/13 / (-12/13) = (5*13) / (13*12) = 5/12

ctgα = cosα / sinα = -12/13 / (-5/13) = (12*13) / (13/5) = 12/5 = 2.4