X ^ 2-2 radical 3x + 2 = 0

X ^ 2-2 radical 3x + 2 = 0

（x-√3)^2-1=0
x=√3±1

There is a set of formulas: 1 + 1, 2 + 3, 3 + 5, 1 + 7, 2 + 9, 3 + 11, 1 + 13 So what is the sum of the 1999 formula______ ．

If SN is used to express the sum of formulas, then S1 = 2, S2 = 5, S3 = 8, s (3N + 1) = 2 + 6N, s (3N + 2) = 5 + 6N, s (3N + 3) = 8 + 6N, 1999 △ 3 = 666 1 = (3 × 666 + 1) = s (6 × 666 + 2) = s (3998), so the answer is: 3998

1 / 3 × 2 / 5 + 1 / 5 × 2 / 7 + 1 / 7 × 2 / 9 + 1 / 9 × 2 / 11 + 1 / 11 × 2 / 13 formula

=1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13
=1/3-1/13
=10/39