Point Discontinuity

Definition of Point Discontinuity

  • A function is said to have a point of discontinuity at x = a or the graph of the function has a hole at x = a, if the original function is undefined for x = a, whereas the related rational expression of the function in simplest form is defined for

x = a. 

Examples of Point Discontinuity

  • Consider a function

This function is undefined for x = 2. But the simplified rational expression of this function, x + 3 which is obtained by canceling (x - 2) both in the numerator and the denominator is defined at x = 2. Thus we can say that the function f(x) has a point of discontinuity at x = 2.

Solved Example on Point Discontinuity

Which of the following would replace the blank so that the rational function  will have a point discontinuity?


A. x - 11

B. 2x + 13

C. Either A or B

D. x + 1

Correct Answer: C


Step 1: The function  will have a point discontinuity if the denominator contains either of the binomials (x - 11) or (2x + 13).

Related Terms for Point Discontinuity

  • Rational Expression
  • Function
  • Graph

Additional Links for Point Discontinuity