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Determining Limits Using Algebraic Properties of Limits

Hannah Hill

Hannah Hill

7 min read

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Study Guide Overview

This study guide covers algebraic properties of limits for AP Calculus AB/BC. It focuses on direct substitution, the limit laws (sum, difference, constant multiple, product, quotient, power, and root rules), and examples of how to apply these rules. It also includes practice questions and exam tips for evaluating limits algebraically.

AP Calculus AB/BC: Mastering Limits Algebraically 🚀

Hey there, future AP Calculus master! Let's dive into the world of limits, but this time, we're ditching the graphs and going full algebra mode. This guide is your go-to resource for acing those limit problems on the AP exam. Let's get started!

1.5 Algebraic Properties of Limits

🔍 Finding Limits with Algebra

The core idea? Plug in the value that x is approaching. It's that simple! But, to make it super smooth, we have a set of rules that help us break down complex limits into simpler parts. Think of these rules as your algebraic superpowers.

Key Concept

Key Concept: Direct substitution is your first move when evaluating limits. If it works, you're done! If not, we have other tools.

Limit Laws: Your Algebraic Toolkit

If limxcf(x)=Llim_{x \to c} f(x) = L and limxcg(x)=Mlim_{x \to c} g(x) = M, where L, M, and c are real numbers, then:

  • Sum Rule: limxc[f(x)+g(x)]=L+Mlim_{x \to c} [f(x) + g(x)] = L + M
  • Difference Rule: limxc[f(x)g(x)]=LMlim_{x \to c} [f(x) - g(x)] = L - M
  • Constant Multiple Rule: limxc[kf(x)]=kLlim_{x \to c} [k \cdot f(x)] = k \cdot L
  • Product Rule: limxc[f(x)g(x)]=LMlim_{x \to c} [f(x) \cdot g(x)] = L \cdot M
  • Quotient Rule: limxcf(x)g(x)=LMlim_{x \to c} \frac{f(x)}{g(x)} = \frac{L}{M}, provided M0M \neq 0
  • Power Rule: limxc[f(x)]n=Lnlim_{x \to c} [f(x)]^n = L^n, where n is a positive integer
  • Root Rule: limxcf(x)n=Ln=L1nlim_{x \to c} \sqrt[n]{f(x)} = \sqrt[n]{L} = L^{\frac{1}{n}}
Memory Aid

Memory Aid: Think of these rules like cooking recipes. You can combine ingredients (functions) using addition, subtraction, multiplication, and division. Just remember to handle each part separately, then combine the results! </me...

Question 1 of 11

What is the value of limx2(x2+3x1)lim_{x \to 2} (x^2 + 3x - 1)? 🎉

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