Let P(n) =
P(1) is true.
Let us assume P(k) is true.

To prove P(k+1) is true using P(k)
….1

=
= =
=
Which is the R.H.s of (1)
P(K+1) is true.
By the Principle of mathematical induction, P(n) is true for all values of n where n N
Hence proved.