First of all, notice that the denominator is always 1 more than the numerator (the first term is 0/1).

So numerator = n, denominator = n + 1.

Also notice that the terms have alternating sign.

When n is odd, the terms are negative, when n is even, the terms are positive. What happens in the case of ? The exact same thing. So we multiply each term by . This will alternate the signs.

So each term is of the form...

, where