Skip to main content
Indietro

Limits and Continuity from a Graph – Step-by-Step Study Guide

Guida di studio - Note intelligenti

Appunti personalizzati basati sui tuoi materiali, ampliati con definizioni chiave, esempi e contesto.

Q1. Find using the graph.

Background

Topic: One-Sided Limits from a Graph

This question tests your ability to determine the left-hand limit of a function at a specific point by analyzing its graph. The left-hand limit, , is the value that approaches as approaches from the left.

Key Terms and Formulas:

  • Left-hand limit:

  • Graphical approach: Trace the curve as approaches from values less than $a$.

Graph of a function with open and closed circles at key points

Step-by-Step Guidance

  1. Locate on the -axis of the graph.

  2. Observe the behavior of as approaches from the left (values less than $-1$).

  3. Follow the curve from the left side and see what -value the function is approaching as gets closer to .

  4. Identify if the function approaches a specific -value, or if there is a jump, hole, or asymptote at .

Try solving on your own before revealing the answer!

Final Answer:

As approaches from the left, the graph approaches the -value of .

This is determined by tracing the curve from the left side of and observing the -value it gets close to.

Q2. Find using the graph.

Background

Topic: One-Sided Limits from a Graph

This question asks you to determine the right-hand limit of a function at a specific point by analyzing its graph. The right-hand limit, , is the value that approaches as approaches from the right.

Key Terms and Formulas:

  • Right-hand limit:

  • Graphical approach: Trace the curve as approaches from values greater than $a$.

Graph of a function with open and closed circles at key points

Step-by-Step Guidance

  1. Find on the -axis of the graph.

  2. Look at the behavior of as approaches from the right (values greater than $-1$).

  3. Follow the curve from the right side and see what -value the function is approaching as gets closer to .

  4. Check if the function approaches a specific -value, or if there is a discontinuity at .

Try solving on your own before revealing the answer!

Final Answer: $5$

As approaches from the right, the graph approaches the -value of $5$.

This is seen by tracing the curve from the right side of and observing the -value it gets close to.

Q3. What is ?

Background

Topic: Evaluating a Function from a Graph

This question asks you to find the value of the function at a specific point by looking at the graph. is the -value of the function at .

Key Terms and Formulas:

  • Function value: is the -coordinate of the point on the graph where .

  • Closed circle: Indicates the function is defined at that point.

  • Open circle: Indicates the function is not defined at that point.

Graph of a function with open and closed circles at key points

Step-by-Step Guidance

  1. Locate on the -axis of the graph.

  2. Look for a closed (filled-in) circle at to determine the value of .

  3. If there is a closed circle, the -value at that point is .

  4. If there is an open circle, is not defined at that -value; check for a closed circle at a different $y$-value at .

Try solving on your own before revealing the answer!

Final Answer: $5$

At , there is a closed circle at , so .

Q4. Find using the graph.

Background

Topic: Two-Sided Limits from a Graph

This question tests your understanding of the two-sided limit at a point. The two-sided limit exists only if both the left-hand and right-hand limits exist and are equal.

Key Terms and Formulas:

  • Two-sided limit:

  • Exists if:

Graph of a function with open and closed circles at key points

Step-by-Step Guidance

  1. Recall the left-hand and right-hand limits you found for .

  2. Compare the values of and .

  3. If the two one-sided limits are not equal, the two-sided limit does not exist at .

  4. If they are equal, the two-sided limit is that common value.

Try solving on your own before revealing the answer!

Final Answer: DNE (Does Not Exist)

The left-hand and right-hand limits at are not equal, so the two-sided limit does not exist.

Q5. Is continuous at ?

Background

Topic: Continuity from a Graph

This question tests your understanding of the definition of continuity at a point. A function is continuous at if the following three conditions are met:

  • is defined

  • exists

Key Terms and Formulas:

  • Continuity at : is defined, exists, and

Graph of a function with open and closed circles at key points

Step-by-Step Guidance

  1. Check if is defined by looking for a closed circle at .

  2. Determine if exists by comparing the left and right limits.

  3. If both are true, check if the limit equals the function value at .

  4. If any of these conditions fail, the function is not continuous at .

Try solving on your own before revealing the answer!

Final Answer: No

The function is not continuous at because the two-sided limit does not exist, even though is defined.

Pearson Logo

Study Prep