Question

Sendo sen x = −1/4, com π < x <3/2, determine tag x .

Answer 1

Propriedade:
sen²x+cos²x=1 ==> cos²x=1-sen²x =1-(-1/4)²=1-1/16=15/16
cos²x=15/16 ==> cosx=+/-√(15/16)=+/-(√15)/4
como π < x < 3/2π ==> cosx=(√15)/4

tagx=senx/cosx=(-1/4)/(√15)/4=-1/√15*(√15/√15)=-√15/15

Resposta: tagx =-√15/15