Question 180514: If cos A>0 and tan A <0, then A is an angle in quadrant?
Answer by mgmoeab(37) (Show Source):
You can put this solution on YOUR website! 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.
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