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GATE 2024 MA – Question 55

Real Analysis · Sequences and Series of Functions · 2 marks · Multiple select

Let S={f_n:n≥1}⊂C[0,1], f_n(x)=xe^(−nx), with supremum metric. Which statements hold?

  1. S is equicontinuous.
  2. S is closed.
  3. S is bounded.
  4. S is compact.

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Show answer and explanation

Correct answer: (A) S is equicontinuous.; (C) S is bounded.

Explanation

For t=nx≥0, |f_n′|=|1−t|e⁻ᵗ≤1, so the family is uniformly Lipschitz, proving A. Supremum norm is 1/(en)≤1/e, proving C. These norms tend to zero, but the zero function is not in S. Thus S is not closed and cannot be compact in this metric space. **A,C**.

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