,

1,,

52152011547665120100908070 ABCD

x23x10(x1)23x23x0x22x4

2;,,

ABCD

12,n3. ,n .

3,,2009

(2008 )1910. 19 B ABCD

2009 ,,

2008 61261161261613

09 ,, ,,

,0814-1

,

,

,,,,

(08) 10.40.20.34.4 A11.5B11.75C11.8D12.25

O2OABMCOAB.ACBCMDEDE.AB=2.(1)C2DE3tanABC=y=x0