giúp Tiên vs mọi người

Cho tam giác ABC" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ABCABC nhọn có tâm nội tiếp I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II. Đường thẳng qua I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II vuông góc với AI" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">AIAI cắt cạnh CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB lần lượt tại M,N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">M,NM,N. Gọi E" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EE đối xứng C" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CC qua M" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">MM, F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">FF đối xứng B" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">BB qua N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">NN. Giả sử E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F đều lần lượt thuộc các đoạn thẳng CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB. Gọi (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) lần lượt là đường tròn ngoại tiếp các tam giác ICE,IBF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ICE,IBFICE,IBF.Chứng minh rằng (K)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K)(K) và (L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(L)(L) tiếp xúc nhau tại I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II.Gọi EF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EFEF theo thứ tự cắt (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) tại P,Q" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">P,QP,Q khác E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F. Chứng minh rằng EP=FQ" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EP=FQEP=FQ.

Đường tròn

giúp Tiên vs mọi người

Cho tam giác ABC" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ABCABC nhọn có tâm nội tiếp I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II. Đường thẳng qua I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II vuông góc với AI" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">AIAI cắt cạnh CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB lần lượt tại M,N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">M,NM,N. Gọi E" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EE đối xứng C" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CC qua M" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">MM, F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">FF đối xứng B" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">BB qua N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">NN. Giả sử E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F đều lần lượt thuộc các đoạn thẳng CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB. Gọi (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) lần lượt là đường tròn ngoại tiếp các tam giác ICE,IBF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ICE,IBFICE,IBF.Chứng minh rằng (K)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K)(K) và (L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(L)(L) tiếp xúc nhau tại I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II.Gọi EF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EFEF theo thứ tự cắt (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) tại P,Q" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">P,QP,Q khác E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F. Chứng minh rằng EP=FQ" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EP=FQEP=FQ.

Đường tròn

giúp Tiên vs moi người

Cho tam giác ABC" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ABCABC nhọn có tâm nội tiếp I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II. Đường thẳng qua I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II vuông góc với AI" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">AIAI cắt cạnh CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB lần lượt tại M,N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">M,NM,N. Gọi E" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EE đối xứng C" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CC qua M" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">MM, F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">FF đối xứng B" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">BB qua N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">NN. Giả sử E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F đều lần lượt thuộc các đoạn thẳng CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB. Gọi (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) lần lượt là đường tròn ngoại tiếp các tam giác ICE,IBF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ICE,IBFICE,IBF.Chứng minh rằng (K)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K)(K) và (L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(L)(L) tiếp xúc nhau tại I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II.Gọi EF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EFEF theo thứ tự cắt (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) tại P,Q" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">P,QP,Q khác E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F. Chứng minh rằng EP=FQ" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EP=FQEP=FQ.

Đường tròn

giúp Tiên vs mọi người

Cho tam giác ABC" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ABCABC nhọn có tâm nội tiếp I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II. Đường thẳng qua I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II vuông góc với AI" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">AIAI cắt cạnh CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB lần lượt tại M,N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">M,NM,N. Gọi E" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EE đối xứng C" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CC qua M" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">MM, F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">FF đối xứng B" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">BB qua N" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">NN. Giả sử E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F đều lần lượt thuộc các đoạn thẳng CA,AB" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">CA,ABCA,AB. Gọi (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) lần lượt là đường tròn ngoại tiếp các tam giác ICE,IBF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">ICE,IBFICE,IBF.Chứng minh rằng (K)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K)(K) và (L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(L)(L) tiếp xúc nhau tại I" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">II.Gọi EF" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EFEF theo thứ tự cắt (K),(L)" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">(K),(L)(K),(L) tại P,Q" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">P,QP,Q khác E,F" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">E,FE,F. Chứng minh rằng EP=FQ" role="presentation" style="display: inline-block; line-height: 0; font-size: 16.38px; word-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; padding-top: 1px; padding-bottom: 1px; position: relative;">EP=FQEP=FQ.

Đường tròn