Bài 1: tính M :N biết:
a) N=\(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+.......+\dfrac{1}{2007}+\dfrac{1}{2008}\) và M= \(\dfrac{2007}{1}+\dfrac{2006}{2}+\dfrac{2005}{3}+.......+\dfrac{2}{2006}+\dfrac{1}{2007}\)
b) M= \(\dfrac{1}{11.13}+\dfrac{1}{13.15}+\dfrac{1}{15.17}+.......+\dfrac{1}{31.33}+\dfrac{1}{33.35}\) và N= \(\dfrac{12}{11.13.15}+\dfrac{12}{13.15.17}+\dfrac{12}{15.17.19}+.....+\dfrac{12}{31.33.35}\)