正方形ABCD中,BE平行于AC,CA=CE,EC的延长线相交于点F,求证:AE=AF延长线与BA的延长线相交于F http://hi.baidu.com/%B8%B4%CB%D5%B5%C4%C4%A7%CA%A5/album/item/6234638fce884cc3513d92b2.html
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/13 06:01:22
![正方形ABCD中,BE平行于AC,CA=CE,EC的延长线相交于点F,求证:AE=AF延长线与BA的延长线相交于F http://hi.baidu.com/%B8%B4%CB%D5%B5%C4%C4%A7%CA%A5/album/item/6234638fce884cc3513d92b2.html](/uploads/image/z/2395099-19-9.jpg?t=%E6%AD%A3%E6%96%B9%E5%BD%A2ABCD%E4%B8%AD%2CBE%E5%B9%B3%E8%A1%8C%E4%BA%8EAC%2CCA%3DCE%2CEC%E7%9A%84%E5%BB%B6%E9%95%BF%E7%BA%BF%E7%9B%B8%E4%BA%A4%E4%BA%8E%E7%82%B9F%2C%E6%B1%82%E8%AF%81%3AAE%3DAF%E5%BB%B6%E9%95%BF%E7%BA%BF%E4%B8%8EBA%E7%9A%84%E5%BB%B6%E9%95%BF%E7%BA%BF%E7%9B%B8%E4%BA%A4%E4%BA%8EF+http%3A%2F%2Fhi.baidu.com%2F%25B8%25B4%25CB%25D5%25B5%25C4%25C4%25A7%25CA%25A5%2Falbum%2Fitem%2F6234638fce884cc3513d92b2.html)
正方形ABCD中,BE平行于AC,CA=CE,EC的延长线相交于点F,求证:AE=AF延长线与BA的延长线相交于F http://hi.baidu.com/%B8%B4%CB%D5%B5%C4%C4%A7%CA%A5/album/item/6234638fce884cc3513d92b2.html
正方形ABCD中,BE平行于AC,CA=CE,EC的延长线相交于点F,求证:AE=AF
延长线与BA的延长线相交于F
http://hi.baidu.com/%B8%B4%CB%D5%B5%C4%C4%A7%CA%A5/album/item/6234638fce884cc3513d92b2.html
正方形ABCD中,BE平行于AC,CA=CE,EC的延长线相交于点F,求证:AE=AF延长线与BA的延长线相交于F http://hi.baidu.com/%B8%B4%CB%D5%B5%C4%C4%A7%CA%A5/album/item/6234638fce884cc3513d92b2.html
设AB=1.作EH⊥AC.CE=CA=√2.EH=BD/2=√2/2.sin∠ECH=1/2.∠ECH=30°
∠EAC=(180°-30°)/2=75°.∠EAF=75°-45°=30°.∠AEC=75°
∠AFE=180-30°-75°=75°=∠AEF .∴AE=AF.
图!图!没图怎么做?!
EC的延长线和谁相交于F?
作EG垂直AC于G . EG=1/2(BD). EG/EC=1/2 .角ECA=30 .AC=CE .角EAC=75=角AEC = 角AFE=角ACE+角BAC=45+30=75 .AF=AE