Good observation, In Portugal we learned it using the proof ot the squezze theorem, and that is the correct way. I am actually a mathematician. the intuitive aproach used in the lesson only had the benefit of spare the students the intrincacy of point set topology in its basic sense.####[['proof', 'Mathematical_Related_Concept', 'POS'], ['intuitive aproach', 'Mathematical_Related_Concept', 'NEG']]