Sir jab hum normal form wale ques.mai last m theta ki value nikalte hai ..suppose meri cos aur sin ki value -ve aa rahi hai to mai usko kaise change kruu 180 +theta or 270-theta....lakin hamare ans sirf add krne par hi aa Raha hai .....subtract krne pr kyu Nahi??? Plz reply sir as soon as possible..thanku in advance