Correct Answer :
Solution :
The correct options are (-1, 1) ∈ S and (1, -1) ∈ S.
Step 1: Simplify the asymptotic behavior of the functions as x → ∞
As (i.e. ):
1. , so using the standard limit , we have:
2. For the logarithmic term in the denominator:
Step 2: Rewrite the overall expression
Substituting these asymptotic approximations into the given limit expression:
Step 3: Analyze the convergence condition for the limit
Since is a bounded function oscillating continuously in the range , the entire limit will evaluate to if and only if the remaining algebraic factor decays to zero:
For polynomial-versus-logarithmic growth rates as :
- If , the negative exponent of places it in the denominator with a positive power. Since power functions grow strictly faster than any logarithmic power, the limit is for any value of .
Step 4: Check the given options
1. For option (-1, 1): Here and . Since , it satisfies the condition. Hence, .
2. For option (1, -1): Here and . Since , it also satisfies the condition. Hence, .
Access expert-curated educational resources and study materials—completely free.
Create, conduct, and manage professional online assessments with Mindyard. Perfect for teachers and institutes.
Copyright © 2026 Mindyard. All Rights Reserved.