CMR 1/41+1/42+1/43+...+1/79+7/80 <7/12
Cmr 1/41+4/42+4/43+.........+1/79+1/80>7/12
CMR: \(\frac{1}{41}+\frac{1}{42}+\frac{1}{43}+...+\frac{1}{80}>\frac{ }{ }\)7/12
chung to :1/41+1/42+1/43+.....+1/80>7/12
CM:1/41 + 1/42+1/43+...+1/79+1/80 >7/12
Chứng tỏ: 1/41+1/42+1/43+.........+1/80 > 7/12
Chứng minh : 7/12<1/41+1/42+1/43+........+1/80<1
chứng tỏ 1/41+1/42+1/43+.......+1/79+1/80>7/12
Chứng tỏ rằng: 1/41+1/42+1/43+...+1/79+1/80>7/12
