Chapter 1: Problem 27
Find the limits. $$ \lim _{x \rightarrow 2^{+}} \frac{1}{|2-x|} $$
Short Answer
Expert verified
The limit is \( +\infty \).
Step by step solution
01
Analyzing the Limit Definition
We're tasked with finding the limit of a function as x approaches 2 from the right, denoted as \( x \to 2^+ \). The function given is \( \frac{1}{|2-x|} \). First, understand that as \( x \to 2^+ \), \( 2-x \) will be a small positive number since \( x > 2 \).
02
Simplifying the Absolute Value Expression
Since \( x \to 2^+ \) implies \( x > 2 \), the absolute value expression \(|2-x|\) simplifies to \(x-2\). This means our limit expression becomes \( \lim_{x \to 2^+} \frac{1}{x-2} \).
03
Evaluating the Limit
Now we evaluate the limit \( \lim_{x \to 2^+} \frac{1}{x-2} \). As \( x \to 2^+ \), the expression \( x-2 \) approaches 0 from the positive side. Thus, \( \frac{1}{x-2} \) approaches infinity because we are dividing 1 by a number that is getting very close to 0 from the positive side.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
One-Sided Limits
In calculus, limits help us understand how a function behaves near a point. Sometimes, we specifically look at how the function behaves as we approach a point from one side only. This is called a **one-sided limit**.
When we say \( \lim_{x \to 2^+} \), we mean we are looking at the limit as \( x \) approaches 2 from values that are greater than 2. This is not about getting to 2 from both directions, just from the right.
Understanding one-sided limits helps us examine behaviors near boundaries or edges of intervals. For instance:
When we say \( \lim_{x \to 2^+} \), we mean we are looking at the limit as \( x \) approaches 2 from values that are greater than 2. This is not about getting to 2 from both directions, just from the right.
Understanding one-sided limits helps us examine behaviors near boundaries or edges of intervals. For instance:
- If approaching from the right, we note it as \( x \to a^+ \).
- If approaching from the left, it’s noted as \( x \to a^- \).
Functions
Functions are basic in mathematics. They take an input and provide an output based on a rule. In the limit we are considering, our function is \( \frac{1}{|2-x|} \).
The key action for this function is division by the absolute value of another expression. Absolute values ensure numbers are non-negative, which affects behavior as we approach specific points.
Here’s how functions generally operate:
The key action for this function is division by the absolute value of another expression. Absolute values ensure numbers are non-negative, which affects behavior as we approach specific points.
Here’s how functions generally operate:
- They can involve simple operations like addition and subtraction.
- Functions can also include more complex operations like division and absolute values - as seen in this problem.
Infinity in Limits
Infinity often appears in limits when values grow very large or small. In the context of our problem, as \( x \to 2^+ \), the denominator \( x-2 \) shrinks toward zero.
As the denominator gets extremely small but stays positive, the value of the function \( \frac{1}{x-2} \) becomes very large - heading towards infinity.
Here’s what happens with infinity in limits:
As the denominator gets extremely small but stays positive, the value of the function \( \frac{1}{x-2} \) becomes very large - heading towards infinity.
Here’s what happens with infinity in limits:
- When the denominator approaches zero, the fraction grows large.
- If coming from the positive side, this means it goes toward positive infinity.
- This behavior illustrates the kind of things limits help us to approximate and understand without direct computation.