CHỨNG TỎ
\(\frac{1}{41}+\frac{1}{42}+\frac{1}{43}+......+\frac{1}{99}+\frac{1}{100}>\frac{7}{10}\)
CMR 1/41+1/42+1/43+...+1/79+7/80 <7/12
cmr;M=1/41+1/42+1/43+..+1/80>7/12
Cmr 1/41+4/42+4/43+.........+1/79+1/80>7/12
Chứng tỏ rằng: 1/41 + 1/42 + 1/43 + 1/44 +...+ 1 60 > 1 3
Chứng tỏ rằng: 1/41 + 1/42 + 1/43 + 1/44 +...+ 1/60 > 1/3
Tính : a, S = 1+4+7+10+13+......+301 b,S= 1+5+9+13+.....+ .... c, S= 1+2-3-4+5+6-7-8+9+10-11-12+..... +41+42-43-44 d, S= 2.1+2.2+2.3+2.4+....+2.99 mình đang can khan cap nho cac ban lam cho minh ti voi
Chứng Tỏ rằng
1/41 +1/42+1/43+1/44+...+1/80<5/6
Chứng tỏ rằng:
1/41+1/42+1/43+1/44....+1/59+1/60>17/45