Question

Seja sen x = 1/3, com 0
a) cos x
b) tg x
c) cos ² x
d) cos 2 x
e) sen 2
f) cotg ² x

Answer 1

cos² x = 1 - sen² x
cos² x = 1 - (1/3)²
cos² x = 1 - 1/9
cos² x = 8/9 = √8/3

tg x = sen x/cos x
tg x = 1/3/√8/3
tg x = 1/√8 = √8/8

cos 2x = cos² x - sen² x
cos 2x = 8/9 - 1/9 = 7/9

sen 2x = 2sen xcos x
sen 2x = 2.1/3.√8/3 = 2√8/9