Question

chứng tở rằng 1 + 1/2 + 1/3 + 1/4 + 1/5 + 1/6 + 1/7 + 1/8 + 1/9 + 1/10 + 1/11 + 1/12 + 1/13 + 1/14 + 1/15 + 1/16 +  1/17 + 1/18 + 1/ 19 + 1/20 + 1/21 + 1/22 + 1/ 23 + 1/24 + 1/25 + 1/26 + 1/27 + 1/28 + 1/29 + 1/30 + 1/31 + 1/32 < 3

Answer 1

de lam ban oi!

Answer 2

ta có

1/2<1/1.2

1/3<1/2.3

...

1/32<1/31.32

=>1/2+1/3+...+1/32<1/1.2+1/2.3+...+1/31.32

=>1/2+1/3+...+1/32<1/1-1/2+1/2-1/3+...+1/31-1/32

=>1/2+1/3+...+1/32<1/1-1/32=31/32

vì 31/32<1

=>tổng đó <1

ta lại có 1+1=2 mà 2 <3

=>tổng đó <3

vậy:-------(bn tự lm nha)

k cho mik vs nha