Question Detail

MTH 101 Mathematical Induction Objective Question

Question

Prove by induction that n! > 2^n for n > 4.
Options
A True
Correct Answer
B False
C Only for n ≥ 5
D Only for n ≥ 6
Correct Answer

Option A is the correct answer.

Detailed Explanation

Base case n=5: 5! = 120 > 2^5 =32 ✔. Assume n=k: k!>2^k. For n=k+1: (k+1)! = (k+1)×k! > (k+1)×2^k > 2×2^k=2^{k+1} ✔ since k+1>2 for k>4.

Hint

Multiply inequality by (k+1) and compare with 2^(k+1).

Question Info