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