Question

Determinando o valor de B=sec 60º + cossec 30 º temos  :

a) 0
b) 2
c) 4
d) nda

Answer 1

sec x = 1 / cos x             
sec 60° = 1 / cos 60°
sec 60° = 1 / (1/2)
sec 60° = 2

cossec 30° = 1 / sen 30°
cossec 30° = 1 / (1/2)
cossec 30° = 2

sec 60° + cossec 30° = 2 + 2 = 4 letra ( c )