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Limits and Continuity

Benjamin Wright

Benjamin Wright

10 min read

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Study Guide Overview

This study guide covers limits and continuity in AP Calculus AB/BC. Key topics include: average and instantaneous rates of change, defining and estimating limits (from graphs and tables), algebraic properties and manipulations of limits, the Squeeze Theorem, types of discontinuities, defining continuity at a point and over an interval, removing discontinuities, asymptotes, and the Intermediate Value Theorem (IVT).

AP Calculus AB/BC: Limits and Continuity - Your Night-Before Guide 🚀

Hey there, future calculus conqueror! This guide is your go-to resource for a final review of limits and continuity. Let's make sure you're feeling confident and ready to ace that exam! Remember, this unit is about 10-12% of the AP Calculus AB exam and 4-7% of the AP Calculus BC exam, so let's get it down!

Introduction to Calculus

The Big Question: Can Change Happen Instantly?

Calculus is all about change and motion. We're diving into whether change can occur at a single moment. Think of an arrow moving across a screen. It seems to jump from one spot to the next, but is it truly instantaneous? This leads us to the concept of the limit.

1.1 Introducing Calculus: Average vs. Instantaneous Rate of Change

Key Concept
  • Average Rate of Change (AROC): The slope of the secant line between two points on a function. It's like finding the average speed over a time interval.
    • Formula:
      f(b)f(a)ba\frac{f(b) - f(a)}{b - a}
    • Instantaneous Rate of Change (IROC): The slope of the tangent line at a single point on a function. It's like finding the speed at a specific moment. We'll get to this using limits!

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Image courtesy of Medium.
Quick Fact
  • AROC is undefined when the denominator is zero (division by zero is a big no-no!).

1.2 Defining Limits and Using Limit Notation

What is a Limit?

A limit is the value a function approaches as the input (x-value) gets closer to a certain point. It helps us understand what happens at a specific point, even if the function isn't defined there. 💡

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Limit Notation

Memory Aid
  • Read this as: "The limit of f(x) as x approaches 'a' is L."
    • Think of it like this: As x gets super close to 'a', the function f(x) gets super close to L.
lim_xaf(x)=L\lim\_{x \to a} f(x) = L

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1.3 Estimating Limits from Graphs

One-Sided vs. Two-Sided Limits

  • One-Sided Limit: The limit as x approaches a value from either the left or the right.

  • Two-Sided Limit: The limit as x approaches a value from both the left and the right. For a two-sided limit to exist, both one-sided limits must be equal.

Exam Tip
  • If the function appro...

Question 1 of 7

What does the following notation represent? limxaf(x)=L\lim_{x \to a} f(x) = L 🤔

The value of f(x) at x = a

The average rate of change of f(x) from 0 to a

The value that f(x) approaches as x gets arbitrarily close to a

The instantaneous rate of change of f(x) at x=a