Question

[Nguyễn Đăng Hải]

cho A = \(\left(\frac{1}{^{2^2}}-1\right).\left(\frac{1}{3^2}-1\right).\left(\frac{1}{4^2}-1\right).....\left(\frac{1}{100^2}-1\right)\)    so sánh A với \(\frac{-1}{2}\)