... sao cho tan= tan , kx m x k Z 4: = m (4) , k xkZ sao cho cot= ... = m (2) * |m| >1, (2) * |m| 1, sao cho cos= m 2cos2 , kxkmxk Z 3: = ... = m (1) * |m| >1, (1) * |m| 1, sao cho sin= 2sin2 , kxkmxk Z 2: =...