Question

Se sen de alfa é 2/3, calcule cos de alfa e tg de alfa

Answer 1

( senx ) 2 + ( cosx ) 2 = 1

( 2 / 3 ) 2 + ( cosx ) 2 = 1

4 / 9 + ( cosx ) 2 = 1
( cosx ) 2 = 1 - 4 / 9
( cosx ) 2 = 9 / 9 - 4 / 9
( cosx ) 2 = 5 / 9
cosx = √5 / √9
cosx = √5 / 3
tg x = 2/ 3 ÷ √5 / 3
tgx = 2 / 3 * 3 / √5
tgx = 2 / √5
tgx = 2√5 / 5