Chứng Tỏ rằng
1/41 +1/42+1/43+1/44+...+1/80<5/6
chứng tỏ rằng :1/41+1/42+1/43+........+2/80>17/12
Chứng tỏ rằng: 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
chứng tỏ rằng : 1/41 + 1/42+ 1/43+...............+ 1/79+ 1/80 >7/12
Hãy chứng tỏ rằng:
a) 1/41+1/42+1/43+...+1/79+1/80>7/12
b)11/15<1/21+1/22+1/23+...+1/59+1/60<3/2
Chứng tỏ 1/41+1/42+1/43+...1/80<5/8
CHỨNG TỎ RẰNG
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
