Respostas

2014-05-05T10:43:50-03:00
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 )
1 5 1