a)CHO A = \(\frac{2}{3^2}\)+ \(\frac{2}{5^2}\) + \(\frac{2}{7^2}\)+.........+ \(\frac{2}{2007^2}\)
CHỨNG MINH RẰNG: A < \(\frac{1003}{2008}\)
b)CHO N = \(\frac{1.4}{2.3}\)+ \(\frac{2.5}{3.4}\)+ \(\frac{3.6}{4.5}\)+.........+ \(\frac{98.101}{99.100}\)
CHỨNG MINH RẰNG: 97 < N < 98
~ giúp mk với~