Math Problem Statement

Given that lim(x → a) f(x) = 0, lim(x → a) g(x) = 0, lim(x → a) h(x) = 1, lim(x → a) p(x) = ∞, and lim(x → a) q(x) = ∞, determine which of the following limits are indeterminate forms: (a) lim(x → a) [f(x) - p(x)], (b) lim(x → a) [p(x) - q(x)], (c) lim(x → a) [p(x) + q(x)]. For indeterminate forms, mark 'I'. For positive infinity, use 'INF'. For negative infinity, use 'NINF'. For cases where the limit doesn't exist or can't be determined, mark 'D'.

Solution

Let's analyze the problem and evaluate the limits provided:

Given limits:

  • limxaf(x)=0\lim_{{x \to a}} f(x) = 0
  • limxag(x)=0\lim_{{x \to a}} g(x) = 0
  • limxah(x)=1\lim_{{x \to a}} h(x) = 1
  • limxap(x)=\lim_{{x \to a}} p(x) = \infty
  • limxaq(x)=\lim_{{x \to a}} q(x) = \infty

We need to classify the following limits:

(a) limxa[f(x)p(x)]\lim_{{x \to a}} [f(x) - p(x)]

  • As f(x)0f(x) \to 0 and p(x)p(x) \to \infty, this results in the form 00 - \infty.
  • A limit in the form 00 - \infty is not indeterminate because subtracting any finite number (0) from \infty results in -\infty.
  • Thus, this limit evaluates to -\infty.

(b) limxa[p(x)q(x)]\lim_{{x \to a}} [p(x) - q(x)]

  • Both p(x)p(x) and q(x)q(x) tend to \infty, so this limit is in the form \infty - \infty.
  • The form \infty - \infty is indeterminate, as the actual behavior depends on how p(x)p(x) and q(x)q(x) approach infinity relative to each other.
  • Thus, this limit is indeterminate (II).

(c) limxa[p(x)+q(x)]\lim_{{x \to a}} [p(x) + q(x)]

  • Both p(x)p(x) and q(x)q(x) tend to \infty, so this limit is in the form +\infty + \infty.
  • A limit in the form +\infty + \infty is not indeterminate and will result in \infty.
  • Thus, this limit evaluates to \infty (INFINF).

Final Answers:

  • (a) -\infty
  • (b) II (Indeterminate)
  • (c) INFINF (\infty)

Would you like more details or explanations on any part of this? Here are a few related questions to deepen your understanding:

  1. What other types of indeterminate forms exist beyond \infty - \infty?
  2. How do you apply L'Hôpital's rule to evaluate indeterminate limits like \infty - \infty?
  3. Why is the form 00 \cdot \infty considered indeterminate?
  4. How does the behavior of p(x)p(x) and q(x)q(x) affect the outcome of the limit in (b)?
  5. Can indeterminate forms always be resolved using algebraic manipulation?

Tip: When evaluating limits, always check if the form is indeterminate before applying advanced techniques like L'Hôpital's rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Indeterminate forms
Infinity behavior in limits

Formulas

-

Theorems

Limit rules
Indeterminate forms identification

Suitable Grade Level

Undergraduate (Calculus I)