求证AE.AB=AF.AC.图我用文字表达下.一个三角形,顶点时A,底边的左边是B,右边是C.BC边上有个点D,AD垂直于BC.AB边上有个点E,DE垂直于AB.AC边上有个点F,DF垂直于AC.顶点是A

求证AE.AB=AF.AC.图我用文字表达下.一个三角形,顶点时A,底边的左边是B,右边是C.BC边上有个点D,AD垂直于BC.AB边上有个点E,DE垂直于AB.AC边上有个点F,DF垂直于AC.顶点是A 如图,已知AE⊥AD,AF⊥AB,AB//CD,AE=CD,AE=AD,AF=CD,求证AC=EF 如图,AD是三角形ABC的中线,AE垂直AC,AF垂直AB,且AE=AC,AF=AB,求证：AD=1/2EF 如图所示,已知AE垂直AB,AF垂直AC,AE=AB,AF=AC,求证.EC垂直BF 如图所示,已知ae⊥ab,af⊥ac,ae=ab,af=ac.求证ec⊥bf 如图,三角形ABC中,AB=AC,且AE=AF,求证EF垂直BC 如图,DE垂直AB,DF垂直AC,DE=DF.求证：AE=AF 如图,已知AD//BC,AD=BC,AE⊥AD,AF⊥AB,AE=AD,AB=AF.求证：AC=EF. 如图,AD∥BC,AD=BC,AE⊥AD,AF⊥AB,且AE=AD,AF=AB,求证：AC=EF. 如图,已知AE⊥AD,AF⊥AB,AF=AB,AE=AD=BC,AD‖BC,求证AC⊥EF 如图,AE垂直于AD,AF垂直于AB,AB平行于CD,AE=AD,AF=CD,求证：AC=EF 如图,已知AE⊥AD,AF⊥AB,AB∥CD,AF=CD,AE=AD,求证：AC垂直EF. 如图,AB=AC,AE=AF,AE垂直于EC于点E,AF垂直于FB与F.求证:角1=角2 如图,AB=AC,AE=AF,AF⊥EC于E,AF⊥FB于F.求证∠1=∠2. 已知:如图,在△ABC中AB=AC,AE是BC边上的中线AF是角CAD的平分线求证AE垂直AF 已知,如图,在△ABC中,AB=AC,AE是C边上的中线,AF是∠CAD的平分线,求证:AE⊥AF 已知,如图,在△ABC中,AB=AC,AE是C边上的中线,AF是∠CAD的平分线,求证:AE⊥AF 已知：如图,EF‖BC,AE²=AD·AB.求证：DF‖EC.【EF‖BC,平行线分直线,成比例AE/AB=AF/AC,AE²=AD·AB,AD/AE=AE/AB=AF/ACDF‖EC】这是解法、可是为什么AD/AE=AE/AB=AF/AC,DF就平行EC、要理由