cmr S = 1/2^2 + 1/3^2 + 1/4^2 + 1/5^2 +......+ 1/200^2 < 1/2
ccmr a = 3/1^2.2^2+5/2^2.3^2+..............+19/9^2.10^2 <1
Loga
Sinh Học lớp 12
