Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 3h 16m
- 11. Integrals of Inverse, Exponential, & Logarithmic Functions2h 34m
- 12. Techniques of Integration7h 39m
- 13. Intro to Differential Equations2h 55m
1. Limits and Continuity
Continuity
Problem 2.5.19
Textbook Question
At what points are the functions in Exercises 13–30 continuous?
y = cos (x) / x

1
Step 1: Understand the concept of continuity. A function is continuous at a point if the limit of the function as it approaches the point from both sides is equal to the function's value at that point.
Step 2: Identify the points where the function might be discontinuous. The function y = cos(x)/x is a rational function, which is typically continuous except where the denominator is zero.
Step 3: Determine where the denominator is zero. Set the denominator x equal to zero and solve for x. In this case, x = 0.
Step 4: Analyze the behavior of the function at x = 0. Since the denominator is zero at x = 0, the function is not defined at this point, indicating a potential discontinuity.
Step 5: Conclude the points of continuity. The function y = cos(x)/x is continuous for all x except at x = 0, where it is undefined.

This video solution was recommended by our tutors as helpful for the problem above
Video duration:
1mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Continuity of Functions
A function is continuous at a point if the limit of the function as it approaches that point equals the function's value at that point. This means there are no breaks, jumps, or holes in the graph of the function at that point. For a function to be continuous over an interval, it must be continuous at every point within that interval.
Recommended video:
Intro to Continuity
Limits
Limits are fundamental in calculus, representing the value that a function approaches as the input approaches a certain point. They are crucial for determining continuity, especially at points where the function may not be explicitly defined. For the function y = cos(x) / x, evaluating the limit as x approaches 0 is essential to assess its continuity at that point.
Recommended video:
One-Sided Limits
Undefined Points
A function can be undefined at certain points, which can affect its continuity. In the case of y = cos(x) / x, the function is undefined at x = 0 because division by zero is not permissible. Understanding where a function is undefined helps identify potential discontinuities and informs the analysis of its overall continuity.
Recommended video:
Critical Points
Related Videos
Related Practice