# Most Calculus Students Can't Solve This But It's REALLY Important | Summary and Q&A

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December 19, 2023
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The Math Sorcerer
Most Calculus Students Can't Solve This But It's REALLY Important

## TL;DR

Two functions can have non-existent limits separately, but have a limit when added together.

## Key Insights

• 🖐️ Limits play a fundamental role in calculus, defining the behavior and properties of functions.
• ⛔ The example illustrates that the existence of the sum of limits does not guarantee the existence of individual limits.
• ⛔ Understanding limit laws is crucial in correctly evaluating limits and avoiding mathematical mistakes.
• 🛟 Harsh mathematical lessons, like this example, can serve as valuable learning experiences.
• 🧑‍🎓 Applying this example in exams helps test the understanding of limits among calculus students.
• 🧑‍🎓 While challenging, once understood, this example simplifies the concept for calculus students.
• 🍹 Recognizing the limitations of the sum does not guarantee the existence of individual limits is essential.

## Transcript

this is something that I actually did not learn until I was in advanced calculus 2 the first time I saw this example I was blown away and at the same time disappointed I had this really really tall tall tall Russian Professor he was super tall and he had a really cool thick accent and he went on the board and he did this example and the reason he d... Read More

### Q: What is the importance of understanding limits in calculus?

Understanding limits is crucial in calculus as they define the behavior and properties of functions, allowing for the study of continuity, derivatives, and integrals.

### Q: Can you explain the limit laws in calculus?

The limit laws state that if the limits of two functions exist individually, then the limit of their sum, difference, product, or quotient also exists, and vice versa.

### Q: Why is it not permissible to break apart the sum of limits if the individual limits do not exist?

Breaking apart the sum of limits relies on the fact that the individual limits exist. If they do not exist, it violates the limit laws and does not hold true.

### Q: How does the given example illustrate the concept?

The example highlights two functions with non-existent limits, but when their limits are added together, the sum has a limit of 0. This demonstrates that the existence of the sum does not imply the existence of individual limits.

## Summary & Key Takeaways

• Calculus teaches that if the limits of individual functions exist, the sum of the limits also exists.

• However, this example demonstrates that the sum existing does not guarantee the existence of individual limits.

• The example involves two functions, f(x) = 1/x and g(x) = -1/x, where their limits do not exist individually but have a limit of 0 when added together.