## Definition 6.3.1: Discontinuous function

If a function fails to be continuous at a point

*c*, then the function is called**discontinuous**at*c*, and*c*is called a**point of discontinuity**, or simply a discontinuity.
If a function fails to be continuous at a point *c*,
then the function is called **discontinuous** at
*c*, and *c* is called a **point of
discontinuity**, or simply a discontinuity.