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由 ET外星人 於 星期一 五月 01, 2006 1:35 am
#ed_op#DIV#ed_cl#需利用相交弦定理#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl#∠#ed_op#/SPAN#ed_cl#LAG=#ed_op#SPAN#ed_cl#∠LHB#ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#∠ALG=#ed_op#SPAN#ed_cl#∠HLB#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#FONT color=#444444 size=2#ed_cl#△#ed_op#/FONT#ed_cl#LAB~#ed_op#FONT color=#444444 size=2#ed_cl#△#ed_op#/FONT#ed_cl#LHB#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#LA/LH=LB/LG#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#LA•LB=LG•LH#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#過L點作任意直線交D圓於G'及H'#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#相交弦定理#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#LG•LH=LG'•LH'=LA•LB#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#所以ABG'H'共圓(圓心在MN線上)#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl#得證#ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl##ed_op#/SPAN#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#
[數學]幾何題..(64)
由 ☆ ~ 幻 星 ~ ☆ 於 星期六 四月 29, 2006 8:42 pm
如圖，現有一圓圓D和元外兩點A,B
做MN射線和AB射線垂直於C
再MN上取一點F
乙FB為半徑畫一圓交元D於G,H
做GH射線交AB設限於L
試證明不管F位置在MN射線上哪理
L都為同一點