/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 43 Calculate the limits in Exercise... [FREE SOLUTION] | 91Ó°ÊÓ

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Calculate the limits in Exercises 21-72 algebraically. If a limit does not exist, say why. $$ \lim _{x \rightarrow-2^{+}} \frac{x^{2}+8}{x^{2}+3 x+2} $$

Short Answer

Expert verified
The limit as x approaches -2 from the right of the given function does not exist because as the denominator tends to 0, the numerator tends to 12, which is a nonzero value.

Step by step solution

01

Check if the denominator tends to 0

As x approaches -2 from the right, let's plug in the value x=-2 in the denominator and check its value: \(x^2 + 3x + 2 = (-2)^2 + 3(-2) + 2 = 4 - 6 + 2 = 0\) Since the denominator tends to 0, we need to analyze the numerator as well.
02

Check if the numerator tends to 0

As x approaches -2 from the right, let's plug in the value x=-2 in the numerator and check its value: \(x^2 + 8 = (-2)^2 + 8 = 4 + 8 = 12\) The numerator tends to 12, which is nonzero.
03

Analyze the limit

Since the denominator tends to 0 and the numerator tends to a nonzero value (12), the limit does not exist. So, the limit as x approaches -2 from the right of the given function does not exist.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Algebraic Limits
When approaching calculus problems, understanding algebraic limits is fundamental. In simple terms, these limits consider the behavior of a function as the input value approaches a specific point. It's like looking at a snapshot of where the function is headed just before reaching that point, without actually getting there.

To analyze these limits algebraically, we use substitution to evaluate the function's behavior. If direct substitution leads to a well-defined value, that's the limit. But when it leads to an undefined expression, such as a division by zero, we need to dig deeper. For example, in the exercise we have the function \( \frac{x^{2}+8}{x^{2}+3x+2} \) and we want to know what happens as \( x \) approaches -2 from the right side. By substituting -2 into the function, we find that the denominator becomes zero, which indicates that we must use other methods, such as factoring or simplifying, to determine the function's limit.
Calculus
Calculus is all about change and motion. It's used to find patterns, calculate areas under curves, and understand the behavior of functions as variables change. With limits, we're at the very heart of calculus. They are the tools we use to describe and predict continuous and often seemingly unpredictable behavior.

In the context of the exercise, we use calculus to find out how a function behaves as we approach a critical point. The operation requires understanding not just the point of interest, but also the direction from which we are approaching (from the left or right). As we try to calculate the limit as \( x \) approaches -2 from the right for the function \( \frac{x^{2}+8}{x^{2}+3x+2} \) and identify that there's a point of discontinuity, we're applying fundamental concepts of calculus. This helps us understand that the function doesn't just go off to infinity randomly but has a reason that's rooted in its algebraic structure - a zero in the denominator.
Indeterminate Forms
In the mystical land of calculus, indeterminate forms are like riddles that seemingly have more than one answer, or sometimes appear to have no answer at all. These occur when a limit evaluates to a form such as 0/0 or ∞/∞, among others. They give us a pause because these ratios don't have a clear-cut value and require further steps to resolve.

In the provided exercise, we approach a potential indeterminate form when attempting to evaluate the limit at \( x = -2 \) from the right. However, closer inspection reveals that the numerator tends to 12, not zero, breaking the spell of indeterminacy and clearly indicating that the limit does not exist due to a division by zero. This understanding is crucial because one may think that every time a denominator goes to zero, we are dealing with an indeterminate form, but it's not always the case. In our example, the limit isn't indeterminate; it is simply non-existent because the function is approaching infinity.

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Most popular questions from this chapter

Compute \(f^{\prime}(a)\) algebraically for the given value of a. HINT [See Example 1.] $$ f(x)=\frac{x}{k}-b(k \neq 0) ; a=12 $$

Annual U.S. sales of bottled water rose through the period 2000–2008 as shown in the following chart The function \(R(t)=12 t^{2}+500 t+4,700\) million gallons \(\quad(0 \leq t \leq 8)\) gives a good approximation, where \(t\) is time in years since 2000 . Find the derivative function \(R^{\prime}(t)\). According to the model, how fast were annual sales of bottled water increasing in \(2005 ?\)

In Exercises 39-44, find the equation of the tangent to the graph at the indicated point. HINT [Compute the derivative algebraically; then see Example \(2(\mathrm{~b})\) in Section \(10.5 .]\) $$ f(x)=x^{2}-3 ; a=2 $$

(Compare Exercise 29 of Section 10.4.) The percentage of mortgages issued in the United States that are subprime (normally classified as risky) can be approximated by $$ A(t)=\frac{15}{1+8.6(1.8)^{-t}} \quad(0 \leq t \leq 9) $$ where \(t\) is the number of years since the start of 2000 . a. Estimate \(A(6)\) and \(A^{\prime}(6)\). (Round answers to two significant digits.) What do the answers tell you about subprime mortgages? b. \(\mathrm{T}\) Graph the extrapolated function and its derivative for \(0 \leq t \leq 16\) and use your graphs to describe how the derivative behaves as \(t\) becomes large. (Express this behavior in terms of limits if you have studied the sections on limits.) What does this tell you about subprime mortgages? HINT [See Example 5.]

(Compare Exercise 30 of Section 10.4.) The value of subprime (normally classified as risky) mortgage debt outstanding in the U.S. can be approximated by $$ A(t)=\frac{1,350}{1+4.2(1.7)^{-t}} \text { billion dollars } \quad(0 \leq t \leq 9) $$ where \(t\) is the number of years since the start of 2000 . a. Estimate \(A(7)\) and \(A^{\prime}(7)\). (Round answers to three significant digits.) What do the answers tell you about subprime mortgages? b. I Graph the function and its derivative and use your graphs to estimate when, to the nearest year, \(A^{\prime}(t)\) is greatest. What does this tell you about subprime mortgages? HINT [See Example 5.]

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