Chứng tỏ 1/41+1/42+1/43+...1/80<5/8
Chứng minh : 7/12<1/41+1/42+1/43+........+1/80<1
Chứng minh rằng: 1/41+1/42+1/43+..........+1/79+1/80>7/12
Chứng minh : 7/12<1/41+1/42+1/43+...+1/80 <1
Chứng minh: \(\dfrac{7}{12}< \dfrac{1}{41}+\dfrac{1}{42}+\dfrac{1}{43}+...+\dfrac{1}{80}< 1\)
A=1\41+1\42+1\43+...+1\79+1\80.chung minh A >7\12
Chững minh rằng : 1/41 + 1/42 + 1/43 +... + 1/79 + 1/80 > 7/12
Chứng minh rằng :
1/41 + 1/42 + 1/43 + ... + 1/79 + 1/80 > 7/12
chứng minh rằng:
1/41+1/42+1/43+.....+1/79+1/80 >7/12