\(\frac{1999x1999}{1995x1995_{ }}=\frac{1999^2}{1995^2}=\left(\frac{1999}{1995}\right)^2\)\(>1^2\)\(=1\)
\(\frac{1999\times1999}{1995\times1995}=\frac{1999^2}{1995^2}>1^2\Rightarrow\frac{1999\times1999}{1995\times1995}>1\)
TL
Bài 1: > 1
Bài 2:
a, 2/3+2/6+2/12+2/24+2/48+2/96+2/192
= 1/1 - 1/3 + 1/3 - 1/6 + 1/6 - 1/12 + 1/12 - 1/24 + 1/24 - 1/48 + 1/48 - 1/96 + 1/96 - 1/192
= 1/1 - 1/192
=191/192
b, 1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
=1/1 - 1/2 + 1/2 - 1/4 + 1/4 - 1/8 + 1/8 - 1/16+ 1/16 - 1/32 + 1/32 - 1/64 + 1/64 - 1/128 + 1/128 - 1/256
=1/1 - 1/256
= 255/256
ks mình nha mỏi quá
tính nhanh p/s 1+ 5/4 + 5/8 + 5/16 + 5/32 + 5/64
