[問題]你的問題
由 tangpakchiu 於 星期日 七月 01, 2007 9:29 pm
#ed_op#DIV#ed_cl#不知對不對...#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#為方便起見,下改Y'為B,X'為A#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#角OXP+角PYO=90度#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#所以O,X,P,Y共圓,角BOP=角XYP#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#角XBY=角XAY=90度,#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#所以X,B,A,Y共圓,角ABY=角AXY#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#要證OP垂直BA,即證角BOP+角OBA=90度#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# 角BOP+角OBA=90度#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#<=>角BOP+角OBA=角OBA+角ABY#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#<=>角BOP=角ABY#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#<=>角XYP=角AXY#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#因XA和PY都垂直PY,#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#所以XA//PY,所以角XYP=角AXY,#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#所以OP垂直BA#ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#