海淀区中考压轴题多解研究

1、?OD=5,?AB=1020XX年海淀区中考压轴题多解研究2006?6?9?n?2?a?065?(163100)?1,?O?AB?GCD?E,?AD?2OC?2OD,?nOD=5.(1)?sinBAD=35?CD?;(2)?ADO!EDO=4!1,?OAC(?1)?(?)?,?)?,?C?C?,?,?2?,?2?G?1?;?E?9?,?.?9?.?3?:?,?F?,?C?7?#?5?1,?b;?B?F?,?#?7?#?5?1.?O,?F?C?a.?,?2000?a?7?8#?x?i?.(1)?CD?:?:?1.?AB?O?,?ADB=9076.?bRt%ABD?,sinBAD=BDAB,?si

2、nBAD=35,?BD1035,?BD=6,AD=AB2-BD2=102-62=8.?DB=76,B&D,?D7AB=D7ABD,=D,?DE(10=8(6,?DE=245?CD=2DE=485.?:?1.?,AD=8.?bRt%ADE?,sinDAE=DEADDE8.?sinBAD=35,?sinDAE=sinBAD,?DE835,?DE=245?CD=2DE=485.?,:?1.?OE=x,?#BE=5-x.?bRt%OED?,DE2=OD2-OE2=52-x2?bRt%BED?,DE2=BD2-BE2=62-(5-x)2?52-x2=62-(5-x)2,?x=75.?DE

3、=OD2-OE2=52-(75)2245.?CD=2ED=485?:?1.?,?,OE=75,?=O+O=5+5,7A7A?1?!?(?%?)A90ACEAACEEAEAE72BE=BO-OE=5-75,?G?1?,DE2=AE7ABE,?DE2=(5+75)(5-75)=57625.?DE=245(?8?C?),?CD=2DE=485.?:?2.?O?OF&AD?F.?AB?O?,?BD&AD,?OF)BD,?,BD=6.?AO=OB,?AF=FD,?OF=12BD=3.?,AD=8.?S%OAD=1OF7AAD=312(3(8=12,?S%OAD=12AO7

4、ADE=12(5(DE52DE,?52DE=12,?OE=245?CD=2ED=485.?:?1.?,AB=10,BD=6,AD=8.?DE?Rt%ABD?AB?O?,?Rt%AED74Rt%ADB,?DEBDADAB,?DE6810,?DE=245,?D=D=485?6?3?G?BD?,?EG.?EG?Rt%BDE?BD?,?EG=12BD=3.?i?%GDE?2%OAD?GDE?12BC?2OAD?12BD,?BBC=BD,?GDE=OAD,?%GDE74%OAD,?DEADEGOD.?AD=8,OD=5,?DE=3(85245,?CD=2ED=485?:?4,?BC?BE?CD?1?,?

5、BC=BD,?%BCD?,?.?OA=OD,?%OAD?,?.?BCD?BD,OAD?12BD,?BCD=OAD,?%BCD74%OAD,?CDADBOOD,?AD=8,BD=6,OD=5,?CD=6(85485.(2)?OAC(?1)?:?:?1.?B?O?,B&D,?B=BD,=D,7A37A2007?3?8C2E.AACCACABAD=CDB,AOC=AOD.?AO=DO,?BAD=ADO.?ADO=4x,?#CDB=4x,?ADO!EDO=4!1,?#EDO=x.?ADO+EDO+EDB=9076,?4x+4x+x=9076,?x=1076,?AOD=18076-(OA

6、D+ADO)=10076,?AOC=AOD=10076.?S?OAC=100360(5212518.?:?1.?,EDO=1076,?bRt%DEO?,DOE=9076-1076=8076,?S?BOD=80360(52509,?S?BOC=S?BOD=509.?S?O=12S=12(52252,S?OAC=S?O-S?BOC,?S?OAC=25250912518.?,:?1.?ADO=OAD,?EOD=2ADO.?ADO!EDO=4!1,?EOD!EDO=8!1.?EOD+EDO=9076,?EOD=89(9076=8076.?COD=2EOD=16076,?COD=36076-16076=20076.?S?CAD=200360(521259,?S?OAC=13S?CAD=12(125912518(?%?,)?&?)?D?4?2?0?,?(054000)?&?b?%?,?,?,?b?,?a?b,?D?.?,?ba?2b?2c?2d?1?,?#a7Ab=c7Ad?!b2=a7Ac?E?,?E.?D?E?=?%?:?1?E?E,?a7Ab=c7Addac?,2=7Abc?!baJ?D?&?F?d?,?,?E?1?,?F?,?=?a?b,?i?D.?,?.?%?:?1?E?E,?&?,?;?=?a