A function is continuous at a point when three things line up: (1) f(a) is defined, (2) the limit as x → a exists, and (3) they are equal. Informally: you can draw through the point without lifting your pen.
A function is continuous at a point when three things line up: (1) f(a) is defined, (2) the limit as x → a exists, and (3) they are equal. Informally: you can draw through the point without lifting your pen.