Giải hộ mình bài 13 vs ạ

`\color{#a8b0b4}{⸻}\color{#91999d}{⸻}\color{#7a8286}{『}\color{#636b6f}{⛧} \color{#4c5356}{E}\color{#434a4d}{m}\color{#3b4244}{p}\color{#32393b}{p} \color{#2a3133}{t}\color{#21282a}{y}\color{#1a2123}{B}\color{#141a1c}{o} \color{#0f1516}{y} \color{#05090a}{⛧}\color{#0a1011}{』}\color{#141a1c}{⸻}\color{#1a2123}{⸻}`

Ta có :

`1/2<2/2=1`

`3/4<4/4=1`

`5/6<6/6=1`

`...`

`199/200<200/200=1`

Vậy `1/2*3/4*5/6*...199/200<1` hay `A^2=(1/2*3/4*5/6*...199/200)<1^2=1`