The smallest positive integer n, for which hold is
1
2
3
4
Let
Step I : For n = 2
which is true. Therefore, P(2) is true.
Step II : Assume that P(k) is true, then P(k):
Step III : For n = k + 1,
......(i)
and ....(ii)
Which is true, hence (ii) is true.
From (i) and (ii),
Hence is true. Hence by the principle of mathematical induction P(n) is true for all
Trick : By check options,
(a) For n = 1, which is wrong
(b) For n = 2, which is correct
(c) For n = 3, which is correct.
(d) For n = 4,
which is correct.
But smallest positive integer n is 2.
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