Find the law 1 / 2 - (3 / 10), 5 / 26 - (7 / 50),. Find the 10th number

Find the law 1 / 2 - (3 / 10), 5 / 26 - (7 / 50),. Find the 10th number

The molecules are odd numbers 1,3,5,7
If the denominator is the numerator square plus 1, the odd term is positive and the even term is negative, so the tenth term is - (19 / 362)