Math Problem Statement

Lim×-->-1 x+4/x+1

Solution

The given limit expression is:

limx1x+4x+1\lim_{{x \to -1}} \frac{x + 4}{x + 1}

Step-by-Step Solution:

  1. Substitute x=1x = -1 directly into the expression:

    Substituting x=1x = -1 into the function: x+4x+1=1+41+1=30\frac{x + 4}{x + 1} = \frac{-1 + 4}{-1 + 1} = \frac{3}{0}

  2. Identify the form: The result is 30\frac{3}{0}, which suggests a division by zero. Since the numerator is not zero, we need to examine the behavior of the function around x=1x = -1.

  3. Check the limit from both sides (Left-hand and Right-hand limits):

    • As x1x \to -1^- (from the left), x+1x + 1 is slightly negative, meaning the denominator approaches 00^-. limx1x+4x+1=30=\lim_{{x \to -1^-}} \frac{x + 4}{x + 1} = \frac{3}{0^-} = -\infty
    • As x1+x \to -1^+ (from the right), x+1x + 1 is slightly positive, meaning the denominator approaches 0+0^+. limx1+x+4x+1=30+=+\lim_{{x \to -1^+}} \frac{x + 4}{x + 1} = \frac{3}{0^+} = +\infty
  4. Conclusion: Since the left-hand and right-hand limits approach negative and positive infinity respectively, the overall limit does not exist.

The limit does not exist.\boxed{\text{The limit does not exist.}}

Would you like further details or have any questions?

Here are 5 related questions for practice:

  1. What is the limit of x21x1\frac{x^2 - 1}{x - 1} as x1x \to 1?
  2. How can we compute limits approaching infinity?
  3. What are the rules for evaluating limits at infinity?
  4. How do we handle indeterminate forms like 00\frac{0}{0}?
  5. How does L'Hopital's rule help in calculating limits?

Tip: When a function gives division by zero, check whether it leads to a finite limit, infinity, or if the limit does not exist by considering behavior from both sides.

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Math Problem Analysis

Mathematical Concepts

Limits
Infinity
Left-hand and Right-hand Limits
Division by Zero

Formulas

Limit expression: lim x -> a f(x)
Right-hand limit: lim x -> a^+ f(x)
Left-hand limit: lim x -> a^- f(x)

Theorems

Limit Theorem
Division by Zero Behavior

Suitable Grade Level

Grades 11-12