H
huyenbach


1: Chứng tỏ :
a, 1-1/2+1/3-1/4+....+1/199-1/200=1/101+1/102+.....+1/199+1/200
b, B=1-1/2^2-1/3^2-1/4^2-....-1/2004^2>1/2004
a, 1-1/2+1/3-1/4+....+1/199-1/200=1/101+1/102+.....+1/199+1/200
b, B=1-1/2^2-1/3^2-1/4^2-....-1/2004^2>1/2004