Question

найдите tg a если cos a=-1/4 и угол a принадлежит 2 четвярти

Answer 1

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)

   

Answer 2

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