Prove the following by using the principle of mathematical induction for all :
Let P(n) :
I. For n = 1,
P(1) : 1
∴ P(1) is true.
II. Let the statement be true for n = m,
∴ P(m) : ... (i)
III. For n = m + 1,
P(m + 1) :
or
From (i),
∴
which is true.
∴ P(m + 1) is true.
∴ P(m) is true P (m + 1) is true
Hence, by principle of mathematical induction, P(n) is true for all