sin a=sqrt(1-(cos a)^2)
sin a=sqrt(1-(-1/4)^2)=sqrt(15)/4
tg a=sin a/cos a=(sqrt(15)/4)/(-1/4)=-sqrt(15)
kkk
sin a=sqrt(1-(cos a)^2)
sin a=sqrt(1-(-1/4)^2)=sqrt(15)/4
tg a=sin a/cos a=(sqrt(15)/4)/(-1/4)=-sqrt(15)
kkk