Chapter 2: Problem 12
Find the limits in Exercises \(11-18\) $$ \lim _{x \rightarrow 1^{+}} \sqrt{\frac{x-1}{x+2}} $$
Short Answer
Expert verified
The limit is 0.
Step by step solution
01
Identify the Type of Limit
The given limit is a one-sided limit as specified by the expression \( x \rightarrow 1^+ \), which means \( x \) is approaching 1 from the right. We'll examine how the function behaves as \( x \) approaches 1.
02
Substitute x = 1 in the function
Attempt to directly substitute 1 into the function: \( \sqrt{\frac{x-1}{x+2}} \). This gives \( \sqrt{\frac{1-1}{1+2}} = \sqrt{\frac{0}{3}} = \sqrt{0} = 0 \). This is straightforward, but we need to confirm that this substitution is valid by examining the behavior around \( x = 1 \).
03
Analyze Behavior of the Function Near x = 1
For values of \( x \) slightly greater than 1 (since we're considering \( 1^+ \)), \( x - 1 \) is a very small positive number, making \( \frac{x-1}{x+2} \) a very small positive quotient. Since the square root of a positive number is also positive, the function remains positive as \( x \) approaches 1 from the right.
04
Evaluate the Limit
Since there is no discontinuity or undefined behavior as \( x \rightarrow 1^+ \), the substitution made in Step 2 holds. Therefore, the limit is \( \lim_{x\rightarrow 1^+} \sqrt{\frac{x-1}{x+2}} = 0 \).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Limits
Limits in calculus are a fundamental concept used to investigate how a function behaves as the input approaches a particular value. They help us understand the behavior of functions, even at points where a direct substitution might not be possible. For example, limits can be employed when functions have undefined points or discontinuities. The notation \( \lim_{x \to a} f(x) \) denotes the value that \( f(x) \) approaches as \( x \) gets closer to \( a \).
- **Finding Limits:** Often involves substituting the point into the function. However, when substitution gives an indeterminate form, other techniques like factoring or rationalizing might be used.
- **Understanding Behavior:** Examining graphs or tables of values can also provide insight into what the function approaches.
One-Sided Limits
One-sided limits provide insight into the behavior of functions from specific directions - either approaching from the left (the negative side) or the right (the positive side). Notation like \( \lim_{x \to a^+} \) is used to describe the limit as \( x \) approaches \( a \) from the right.
- **Right-Side Approach:** Denoted by \( x \to a^+ \), it considers values of \( x \) slightly greater than \( a \). This can reveal unique function characteristics hidden when only considering two-sided limits.
- **Left-Side Approach:** Denoted by \( x \to a^- \), it concerns values slightly less than \( a \).
Continuity
Continuity of a function at a point means the function is smooth and unbroken there. More formally, a function \( f(x) \) is continuous at \( x = a \) if
For a continuous function, one-sided limits from both directions will match and equal the function's value at \( a \). Discontinuities arise from violations of these conditions, such as limits not existing, differing one-sided limits, or the function not being defined at \( a \). Ensuring continuity often involves re-evaluating function definitions around problematic points.
- \( \lim_{x \to a} f(x) \) exists,
- \( f(a) \) is defined,
- And \( \lim_{x \to a} f(x) = f(a) \).
For a continuous function, one-sided limits from both directions will match and equal the function's value at \( a \). Discontinuities arise from violations of these conditions, such as limits not existing, differing one-sided limits, or the function not being defined at \( a \). Ensuring continuity often involves re-evaluating function definitions around problematic points.
Square Roots
The square root function, symbolized by \( \sqrt{x} \), provides a non-negative root of a number. When dealing with expressions within a function, such as \( \sqrt{\frac{x-1}{x+2}} \), understanding how square roots behave is crucial.
- **Positivity:** The square root of a positive number remains positive, and \( \sqrt{0} \) is \( 0 \).
- **Domain Considerations:** Ensure that the expression inside the square root is non-negative, as square roots of negative numbers are not real.