Question 180514
If cos A>0, then cosA is positive
and if tan A <0, then tanA is  negative.
Now, ask yourself---
where is cosx positive? (I AND IV QUADRANT)
where is tanx negative? (II AND IV QUADRANT)

ANGLE A CANT BE IN QUADRANT I BECAUSE IT DOESNT SATISFY THE CONDITION OF tanA BEING NEGATIVE.
ANGLE A CANT BE IN QUADRANT II BECAUSE IT DOESNT SATISFY THE CONDITION OF cosA BEING POSITIVE.

SINCE cosA IS POSITIVE AND tanA IS NEGATIVE IN QUADRANT IV, THEN A IS AN ANGLE IN THIS QUADRANT.