If cos(Θ) = -2/9, and 90° < θ < 180°, what is the value of tan(θ)?
From 90 to 180 degrees sin is POSITIVE
cos2 + sin2 = 1
sin2 = 1-cos2
sin2 =1 - (-2/9)2
sin2 = 77/81
sin = sqrt 77 / 9 (remember : sin is positive )
Then Tan = sin/cos = .............. (it should be negative value)
+37159 
