Question

найдите sin (a), ctg (a) если cos(a) 1/2

Answer 1

cos a=1/2: sin^2 a+cos^2 a =1; sin ^2 a=1-1/4=3/4, sin a=+ - v3/2; ctg a=cos a/sin a=1/2:(+-v3/2)=-+1/ v3