chứng minh rằng:
3 < H =1+1/2+1/3+1/4+......+1/63 <6
Chứng minh rằng H>2
\(H=\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+.......+\frac{1}{63}\)
Ta có: H=(1/2+1/3+1/4)+(1/5+...+1/8)+(1/9+1/16)+(1/17+...+1/63)
=> H=13/12 + (1/5+...+1/8)+(1/9+...+1/16)+(1/17+...+1/63)
=> H> 1 + 4x(1/8) + 8x (1/16) + (1/17+...+1/63)
=> H> 1+ 1/2 + 1/2 + (1/17+...+1/63)
=> H> 1+1+(1/17+...+1/63)
=> H>1+1
=> H>2
chứng minh rằng 1/2+1/3+1/4+...+1/63>2
Cho A= 1+1/2+1/3+1/4+....+1/63. Chứng minh rằng A lớn hơn 3
Bài 6: Cho A =1+1/2+1/3+1/4+...+1/63. Chứng minh rằng: A > 3
Chứng minh rằng: 1/2 + 1/3 + 1/4+...+ 1/63 >2
chứng minh rằng: 1/2+1/3+1/4+...+1/63>2
1/2 + 1/3 < 1/2 + 1/2 = 1
1/4 + 1/5 + .. + 1/7 < 1/4 +..+ 1/4 = 4/4 = 1
1/8 + 1/9 + .. + 1/15 < 1/8 + .. + 1/8 = 8/8 = 1
tương tự
1/16 +1/17 + .. + 1/31 < 1
1/32 + 1/33 + .. + 1/63 < 1
=> cộng lại => B < 2
Chứng minh rằng: 1+1/2+1/3+1/4+...+1/63 < 6
Chứng minh rằng : 2 < 1/2 + 1/3 + 1/4 + ... + 1/63 < 5
Chứng minh rằng:
1/2 + 1/3 + 1/4 + ... + 1/63 > 2