If tan(α) =− 2/5 ; α is in quadrant IV, find cos(α) .
In Q IV sin is neg cos is positive
tan = sin/cos = -2/5
find hypotenuse h^2 = (-2)^2 + 5^2 h = sqrt 29
cos = 5/sqrt29 or 5 sqrt29/29
sin = -2/sqrt 29
+37167 
