1 IA IB Y Y X X0 0 IAB X X2 2 A I B I 2 1 3S X0TA COỰ
1
.
1
.
1
1 .
1
IA IB
y
y x
x
0
0
IAB
x
x
2
2
A
I
B
I
2
1
3
S
x
0
Ta coự :
1 5
.
1
25
haống soỏ
x
5
2
2
1
3
6
x
Vaọy:
S
IAB
khoõng phuù thuoọc vaứo vũ trớ ủieồm M.