xy≤x+y2" role="presentation" style="font-size: 13.696px; display: inline; position: relative;">≤x+y2xy≤x+y2 (BĐT Cosi)=> 3=x+y−xy≥x+y2" role="presentation" style="font-size: 13.696px; display: inline; position: relative;">3=x+y−xy−−√≥x+y23=x+y−xy≥x+y2 => x+y≤6" role="presentation" style="font-size: 13.696px; display: inline; position: relative;">x+y≤6x+y≤64=x+1+y+1≤2[(x+1)+(y+1)]=2(x+y+2)" role="presentation" style="font-size: 13.696px; display: inline; position: relative;">4=x+1−−−−√+y+1−−−−√≤2[(x+1)+(y+1)]−−−−−−−−−−−−−−−√=2(x+y+2)−−−−−−−−−−√4=x+1+y+1≤2[(x+1)+(y+1)]=2(x+y+2)=> x+y+2≥422=8" role="presentation" style="font-size: 13.696px; display: inline; position: relative;">x+y+2≥422=8x+y+2≥422=8 => x+y≥6" role="presentation" style="font-size: 13.696px; display: inline; position: relative;">x+y≥6x+y≥6Dấu bằng có <=> x=y=3" role="presentation" style="font-size: 13.696px; position: relative;">x=y=3x=y=3
xy
≤x+y2"role
="
presentation
"style
="
font-size: 13.696px;
Hi
ển thị n
ội
dòn
g;
vị t
rí: t
ương đối;
"
>≤
x
+
y2xy≤x+y2 (BĐT Cosi)
=> 3=x+y
-xy
≥x+y2"role
="
presentation
"style
="
font-size: 13.696px;
Hi
ển thị n
ội
dòn
g;
vị t
rí: t
ương đối;
"
> 3
=
x
+
y
- x
y
--ó
x
+
y23=x+y
-xy≥x+y2 => x+y
≤6"role
="
presentation
"style
="
font-size: 13.696px;
Hi
ển thị n
ội
dòn
g;
vị t
rí: t
ương đối;
"
> x
+
y≤
6x+y≤64=x+1+y+1
≤2[(x+1)+(y+1)]=2(x+y+2)"role
="
presentation
"style
="
font-size: 13.696px;
Hi
ển thị n
ội
dòn
g; position: relative;
"
> 4
=
x
+
1
----√+
y+
1
----ò
2
[
(
x
+
1
)
+
(
y+
1
)
]
---------------√=
2
(
x
+
y+
2
)
----------√4=x+1+y+1≤2[(x+1)+(y+1)]=2(x+y+2)=> x+y+2
≥422=
số 8"role
="
presentation
"style
="
font-size: 13.696px;
Hi
ển thị n
ội
dòn
g;
vị t
rí: t
ương đối;
"
> x
+
y+
2
≥
422=
8x+y+2≥422=
số 8 => x+y
≥6"role
="
presentation
"style
="
font-size: 13.696px;
Hi
ển thị n
ội
dòn
g;
vị t
rí: t
ương đối;
"
> x
+
y≥
6x+y≥6Dấu bằng <=> x=y=3"role
="
presentation
"style
="
font-size: 13.696px;
vị t
rí: t
ương đối;
"
> x
=
y=
3x=y=3