1.cho c=1/3+1/3 mũ 2 + 1/3 mũ 3 +....+1/3 mũ 98 +1/3 mũ 99. CMR c < 1/2

2.cho d=1/4+/4 mũ 2 +1/4 mũ 3 +....+1/4 mũ 999 +1/4 mũ 1000

CMR 1+1/2+1/3+.......+1/2^1999 >1000

Câu hỏi: CMR: 1+1/2+1/3+....1/2^1999 >1000

CMR:1+1/2+1/3+...+1/2¹⁹⁹⁹>1000

C ={(1+(1999/1))(1+(1999/2))(1+(1999/3))+...+(1+(1999/1000))}/{(1+(1000/1))(1+(1000/2))(1+(1000/3))...(1+(1000/1999))}

A=(1+1999/1).(1+1992/2).(1+1999/3)...(1+1999/1000)/(1+1000/1).(1+1000/2).(1+1000/3)...(1+1000/1999)

Tính A

cho M = 1 + 1/2 + 1/3 +...+1/2 mũ 1999 

Chứng minh M > 1000

giúp mk với nha gấp lắm á 

cảm ơn mn

1.Tính C=\(\frac{\left(1+\frac{1999}{1}\right)\left(1+\frac{1999}{2}\right)\left(1+\frac{1999}{3}\right)...\left(1+\frac{1999}{1000}\right)}{\left(1+\frac{1000}{1}\right)\left(1+\frac{1000}{2}\right)\left(1+\frac{1000}{3}\right)...\left(1+\frac{1000}{1999}\right)}\)

1)CMR :1+12+1/3+..+1/2^1999<1000

2)tím số tự nhiên x biết :1/3+1/3+1/10+...+1/x(x+1)=2013/2015