# How to Evaluate Limits Algebraically in Calculus by Factoring | Summary and Q&A

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May 6, 2022
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The Math Sorcerer
How to Evaluate Limits Algebraically in Calculus by Factoring

## TL;DR

This lecture teaches how to evaluate limits analytically by using the rule: if you can plug in the number and get an answer, go for it, otherwise try something else like factoring.

## Key Insights

• #️⃣ The general rule for evaluating limits analytically is to plug in the number and check if it leads to a real number as an answer.
• 😑 If plugging in the number does not work, alternative techniques like factoring can be utilized to simplify the expression and make it suitable for evaluation.
• 🤘 Writing the limit sign is essential to maintain proper notation and ensure accurate calculations.

## Transcript

hello in this lecture we're going to discuss evaluating limits analytically and we're going to do several examples so that you can learn how to actually evaluate limits so there is a general rule that you can use when evaluating limits and this is not a rule that you typically see written in books but it's a rule that works and you just have to pay... Read More

### Q: What is the general rule for evaluating limits analytically?

The general rule is to plug in the number and see if you get a real number as an answer. If you do, that is the limit. If not, you need to try a different approach.

### Q: Can you explain the importance of writing the limit sign in the calculations?

Writing the limit sign is crucial because it reminds us that we are working with a limit and not just plugging in a number directly. It helps maintain the proper notation and ensures accurate calculation.

### Q: What should be done if plugging in the number results in an indeterminate form, such as zero divided by zero?

In such cases, an alternative technique like factoring can be employed to simplify the expression and eliminate the indeterminate form. Factoring allows us to cancel common factors and make the expression valid for evaluation.

### Q: What are some key techniques used for evaluating limits analytically?

Some key techniques include factoring, using special formulas like the difference of cubes or sum of cubes, simplifying the expression by canceling common factors, and applying algebraic manipulations to transform the expression into a more manageable form.

## Summary & Key Takeaways

• The lecture discusses the general rule for evaluating limits analytically, which involves plugging in the number and getting a real number as an answer.

• If plugging in the number does not work, alternative techniques such as factoring can be used to evaluate the limit.

• Several examples are provided in the lecture to demonstrate the application of the rule and different techniques for evaluating limits.