Question 9954
i am assuming i have understood your stripped down version of the question... Also look into my Lesson of Trig equations, as the explanation is there, more than what i will explain here.


Let angle be A, so cosA=1/2...what is the angle if tanA is negative.


Well, from your calculator, angle A is 60 degrees but if we do tan60, we get a positive angle.


Question is, where is cos +ve but tan -ve? Answer is the 4th quadrant, so the angle we require is actually 300 degrees...


cos300 --> +1/2
tan300 is -ve


jon.