The statement is .

Condition I:

First show that, the above formula is true, when .

When , the formula is .

Condition 1 of the Principle of Mathematical Induction holds.

Condition II :

Assume that holds for some , and determine whether the formula then holds for .

Assume that, for some .

Now need show that,

It follows that,

Thus, Condition II also holds.

The statement is true for all natural numbers.

The statement is true for all natural numbers.