Question

Sabendo que sec x= -3, calcule tg x

Answer 1

sec x = 1/cos x
sen^2 x + cos^2 x = 1
tg x = sen x/ cos x

sec x = -3

-3=1/ cos x
-3.cos x= 1
cos x = -1/3

sen^2 x + (-1/3)^2=1
sen^2 x +1/9=1
sen^2 x =1-1/9
sen^2 x = 9/9-1/9
sen^2 x= 8/9
sen x= V8/9
sen x= 2V2/3

tg x = sen x/cos x
tgx = 2V2/3/-1/3
tg x = 2V2/3.-3/1
tg x= -6V2/3
tg x = -2V2