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A) Basis Step
b) Inductive Step

A) Basis Step b) Inductive Step-example-1
User Unflores
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1 Answer

10 votes
10 votes

Basis step: Let
n=2. Then


2! = 2\cdot1 = 2

and


2^2 = 4

so
2! < 2^2.

Inductive step: Assume
k! < k^k. We want to show that
(k+1)! < (k+1)^(k+1).

Now


(k+1)! = (k+1) \cdot k! \\\\ ~~~~~~~~~~~ < (k+1) \cdot k^k \\\\ ~~~~~~~~~~~ < (k+1) \cdot k^(k+1) \\\\ ~~~~~~~~~~~ < (k+1) \cdot (k+1)^(k+1)

where the first inequality follows from the induction hypothesis; the second follows from multiplying the right side by some
k>2; and the third from adding the remaining terms to complete the binomial expansion
(k+1)^(k+1), all of which are positive since they are some power of
k>2.

QED

User Chenchuk
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