Given Tana = 2 / 3, find Sina times cosa, and then divide by sin's square a minus cos's Square a

Given Tana = 2 / 3, find Sina times cosa, and then divide by sin's square a minus cos's Square a

sinacosa/ (sin²a-cos²a)
= 1/2 sin2a ÷ [1-2cos²a]
= 1/2 sin2a ÷ (-cos2a)
= -1/2 tan2a
= -[tana/(1-tan²a)]
=-2/3 ÷ 5/9
= -6/5