jika 1/2 phi < x< phi dan sinx= 1/3 maka tan x

sin x = 1/3 = de/mi => sa = √(3^2 - 1^2) = √(9 - 1) = √8 = 2√2
Karena 1/2 π < x < π maka
Tan x = - de/sa = - 1/(2√2) . √2/√2 = -1/4 √2