Calculus continuity might sound complex, but it's really about understanding... Show more
AP Calculus AB/BC55 views·Updated May 21, 2026·2 pagesUnderstanding Continuity and One-Sided Limits
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Continuity at a Point and on an Open Interval
Ever wonder if you could draw a function without lifting your pencil? That's essentially what continuity is all about! A continuous function has no holes, jumps, or gaps in its graph.
For a function to be continuous at a point c, three conditions must be met: f(c) must be defined, the limit of f(x) as x approaches c must exist, and that limit must equal f(c). If a function meets these conditions at every point within an interval (a,b), we say it's continuous on that interval.
Not all functions are continuous everywhere. For example, f(x) = 1/x isn't continuous at x = 0 because division by zero isn't defined. Piecewise functions might have discontinuities where the pieces meet, and rational functions can have issues where the denominator equals zero.
Remember This: Discontinuities come in two flavors - removable (where we could "fix" the function by redefining it at a single point) and nonremovable (where no single value can make the function continuous at that point).
When checking a function for continuity, always work through all three conditions systematically. Many functions you'll encounter in basic calculus are continuous everywhere, which is why they're so useful for modeling real-world situations.
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One-Sided Limits
Sometimes we need to approach a point from just one direction - that's where one-sided limits come in handy. The right-hand limit approaches from values greater than the point, while the left-hand limit approaches from values less than the point.
One-sided limits are particularly useful for piecewise functions and graphs with jumps. For a regular limit to exist, both the left-hand and right-hand limits must exist and be equal. If they're different, the overall limit doesn't exist, but we can still describe what happens from each side.
For a function to be continuous on a closed interval [a,b], it needs to be continuous on the open interval (a,b), continuous from the right at a, and continuous from the left at b. This extension allows us to work with functions on bounded domains.
Pro Tip: When evaluating limits of rational functions that give 0/0, try factoring the numerator and denominator to cancel common terms. This technique often reveals the actual limit value, as seen in the example where lim(x→3) / = 1/6.
When tackling limit problems, drawing a quick sketch of the function can help you visualize the behavior from both sides of the point in question. This visual approach often makes the concept of one-sided limits much clearer.
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AP Calculus AB/BC55 views·Updated May 21, 2026·2 pagesUnderstanding Continuity and One-Sided Limits
Calculus continuity might sound complex, but it's really about understanding when functions behave smoothly without breaks or jumps. This concept is crucial because it helps determine where mathematical models accurately represent real-world situations and where they might fail.
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Continuity at a Point and on an Open Interval
Ever wonder if you could draw a function without lifting your pencil? That's essentially what continuity is all about! A continuous function has no holes, jumps, or gaps in its graph.
For a function to be continuous at a point c, three conditions must be met: f(c) must be defined, the limit of f(x) as x approaches c must exist, and that limit must equal f(c). If a function meets these conditions at every point within an interval (a,b), we say it's continuous on that interval.
Not all functions are continuous everywhere. For example, f(x) = 1/x isn't continuous at x = 0 because division by zero isn't defined. Piecewise functions might have discontinuities where the pieces meet, and rational functions can have issues where the denominator equals zero.
Remember This: Discontinuities come in two flavors - removable (where we could "fix" the function by redefining it at a single point) and nonremovable (where no single value can make the function continuous at that point).
When checking a function for continuity, always work through all three conditions systematically. Many functions you'll encounter in basic calculus are continuous everywhere, which is why they're so useful for modeling real-world situations.
2
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One-Sided Limits
Sometimes we need to approach a point from just one direction - that's where one-sided limits come in handy. The right-hand limit approaches from values greater than the point, while the left-hand limit approaches from values less than the point.
One-sided limits are particularly useful for piecewise functions and graphs with jumps. For a regular limit to exist, both the left-hand and right-hand limits must exist and be equal. If they're different, the overall limit doesn't exist, but we can still describe what happens from each side.
For a function to be continuous on a closed interval [a,b], it needs to be continuous on the open interval (a,b), continuous from the right at a, and continuous from the left at b. This extension allows us to work with functions on bounded domains.
Pro Tip: When evaluating limits of rational functions that give 0/0, try factoring the numerator and denominator to cancel common terms. This technique often reveals the actual limit value, as seen in the example where lim(x→3) / = 1/6.
When tackling limit problems, drawing a quick sketch of the function can help you visualize the behavior from both sides of the point in question. This visual approach often makes the concept of one-sided limits much clearer.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in AP Calculus AB/BC
8Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan SiOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha KlichAndroid user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
AnnaiOS user