Question

1) Sabendo que x está no segundo quadrante e que o sen x=4/5, calcule:

a) cos.x =
b) sec x =
c) tan x =
d) cotg x =

Answer 1

SETACO +
12 13 14

a) sen^2 + cos^2 = 1

cos^2 = 1 - (4/5)^2

cos^2 = 1 - 16/25
cos^2 = 25/25 - 16/25
cos^2 = 9/25
cos = V(9/25) = - 3/5 ←←

b) sec = 1/cos = - 5/3 ←←

c) tg = sen/cos = 4/5 / -3/5 = - 4/3 ←←

d) cotg = 1/tg = -3/4 ←←