Question:
If P(n) : n! > 2n – 1, n ∈ N, then P(n) is true for all n > _____________.
Solution:
P(n) : n! > 2n – 1; n ∈
for n = 1,
P(1) : 1! > 21–1
i.e 1 > 2° = 1
i.e 1 > 1
which is false a statement
for n = 2
P(2) : 2! > 22–1
i.e 2 > 21
i.e 2 > 2
which is again a false statement.
for n = 3
P(3) : 3! > 23–1
i.e 6 > 22 = 4
i.e 6 > 4 which is true
for n = 4
P(4) : 4! > 24–1
i.e 24 > 23 = 8 which is true
Hence, P(n) : n! > 2n – 1 is true
for n > 2