Math Problem Statement

Consider the following statements: (i) If lim (x → ∞) f(x) = ∞, lim (x → ∞) g(x) = ∞, and lim (x → ∞) (f(x) / g(x)) = ∞, then f(x) → ∞ slower than g(x) → ∞. (ii) If lim (x → ∞) f(x) = ∞, lim (x → ∞) g(x) = ∞, and lim (x → ∞) (f(x) / g(x)) = 0, then f(x) → ∞ faster than g(x) → ∞. Determine which of the above statements are True (1) or False (2).

Solution

Let's analyze the two given statements:


Statement (i):

If limxf(x)=,limxg(x)=,andlimxf(x)g(x)=,\lim_{x \to \infty} f(x) = \infty, \quad \lim_{x \to \infty} g(x) = \infty, \quad \text{and} \quad \lim_{x \to \infty} \frac{f(x)}{g(x)} = \infty, then f(x)f(x) \to \infty slower than g(x)g(x) \to \infty.

Explanation:
The condition limxf(x)g(x)=\lim_{x \to \infty} \frac{f(x)}{g(x)} = \infty means that f(x)f(x) grows much faster than g(x)g(x) as xx \to \infty. Therefore, the statement that f(x)f(x) grows slower than g(x)g(x) is incorrect.
This statement is False.


Statement (ii):

If limxf(x)=,limxg(x)=,andlimxf(x)g(x)=0,\lim_{x \to \infty} f(x) = \infty, \quad \lim_{x \to \infty} g(x) = \infty, \quad \text{and} \quad \lim_{x \to \infty} \frac{f(x)}{g(x)} = 0, then f(x)f(x) \to \infty faster than g(x)g(x) \to \infty.

Explanation:
Here, limxf(x)g(x)=0\lim_{x \to \infty} \frac{f(x)}{g(x)} = 0 indicates that f(x)f(x) grows slower than g(x)g(x). So, the conclusion that f(x)f(x) grows faster is incorrect.
This statement is False.


Final Answer:

  • (i) is False.
  • (ii) is False.

Would you like further clarification or more details on this? Here are 5 related questions that may help expand your understanding:

  1. What does it mean when a limit of a ratio of two functions tends to infinity?
  2. How can we compare the growth rates of two functions as xx approaches infinity?
  3. What does L'Hopital's rule say about evaluating limits of indeterminate forms?
  4. What are common examples of functions with different growth rates (e.g., exponential, polynomial)?
  5. Can a function grow faster than another even if both approach infinity?

Tip: When comparing functions' growth rates, always check the limit of their ratio to see which one dominates as xx \to \infty.

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Math Problem Analysis

Mathematical Concepts

Limits
Asymptotic Growth
Function Comparison

Formulas

lim (x → ∞) f(x) = ∞
lim (x → ∞) g(x) = ∞
lim (x → ∞) (f(x) / g(x)) = ∞
lim (x → ∞) (f(x) / g(x)) = 0

Theorems

Limit Theorem
Comparison of Growth Rates

Suitable Grade Level

University Level (Calculus)