Question

Dado o cosx= 4/5, com 0 < x < π/2, calcule senx e tgx.

Answer 1

Relação fundamental:...sen² x + cos² x = 1

........................................:....sen² x = 1 - cos² x

.............................................sen² x = 1 - (4/5)²

..............................................sen² x = 1 - 16/25

...............................................sen² x = 9/25

..............................................sen² x = (3/5)².......=> sen x = 3/5

.tg x = sen x / cos x = 3/5 / 4/5...................=> tg x = 3/4