The sequence is .

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Sum of the terms of the arithmetic sequence use the formula: .

Here difference, .

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Let be the statement .

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Condition 1:

For : Because is a true statement is true for .

Condition 1 is satisfied.

Condition 2:

Let us assume that .

is true for the positive integer .

As is true, then must also be true.

The final statement is exactly , Therefore is true.

Condition 2 is also satisfied.

Because is true for and implies .

is true for and so on.

By the principle of mathematical induction is true for all positive integers of .

By the principle of mathematical induction is true for all positive integers of .