Question

[Nguyễn Trúc Phương]

Chứng minh rằng:

a,A=1/2+1/2^2+1/2^3+.+1/2^2<1

b,B=1/3+1/3^2+1/3^3+...+1/3^n<1/2

c,B=1/2-1/2^2+1/2^3-1/2^4+...+1/2^2015-1/2^2016<1/3

d,D=1/3+2/3^2+3/3^3+4/3^4+...+100/3^100<3/4

Answer 1

[Nguyễn Vũ Phương Thảo]

4333344

Answer 2

[Vũ Tuấn Khôi Nguyên]

?reeeeeeeeeeee