Consider the following functions where n is a positive integer: n1/3, log⁡(n),…

2026

Consider the following functions where n is a positive integer:

n1/3, log⁡(n), log⁡(n!), 2log⁡(n)

Which one of the following lists the functions in increasing order of asymptotic growth rate?

Note: Assume the base of log to be 2.

Answer: A. log⁡(n), n1/3, 2log⁡(n), log⁡(n!)ConceptAsymptotic growth compares how positive functions scale as n becomes large. Every fixed positive power of n eventually dominates a logarithm, and…

  1. A.

    log⁡(n), n1/3, 2log⁡(n), log⁡(n!)

  2. B.

    n1/3, log⁡(n), log⁡(n!), 2log⁡(n)

  3. C.

    log⁡(n), n1/3, log⁡(n!), 2log⁡(n)

  4. D.

    2log⁡(n), n1/3, log⁡(n), log⁡(n!)

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Show answer & explanation

Correct answer: A

Concept

Asymptotic growth compares how positive functions scale as n becomes large. Every fixed positive power of n eventually dominates a logarithm, and Stirling’s approximation gives log(n!) = Θ(n log(n)).

The stated base matters here: with base 2, 2log₂(n) = n.

Application

  1. A logarithm is dominated by any positive polynomial power, so log2(n) = o(n1/3).

  2. Using the base-2 identity, 2log₂(n) = n. Since n1/3 = o(n), the fractional-power term comes before this exponential-log term.

  3. Stirling’s approximation gives log2(n!) = Θ(n log₂(n)). Therefore n = o(log₂(n!)).

Cross-check

  • log₂(n) / n1/3 → 0.

  • n1/3 / n = n−2/3 → 0.

  • n / (n log₂(n)) = 1 / log₂(n) → 0.

Result

log2(n) < n1/3 < 2log₂(n) < log2(n!).

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