→ doa2:用外分比公式還真的做的出來..XD 推 140.112.249.46 10/17
※ 引述《cuttlefish (總算要乖乖上課了)》之銘言：
: 由於想賺一些ptt幣
: 再加上不想讓這裡冷掉(雖然早就....)
: 所以我想把一些我以前準備IMO做的題目po上來
: (有些應該是秒殺題吧~^^)
: In triangle ABC , K and L are points on the side BC ( K being closer to B
: than L ) such that BC KL = BK CL , and AL bisects KAC . Show that AL is
: perpendicular to AB
我試著中文化好了@@
三角形ABC中，K和L為BC邊上的兩點(是以B-K-L-C的順序)使得BC乘KL=BK乘CL，
且AL平分角KAC。證明AL垂直AB。
不過...我不會做...||
--
'Oh, Harry, dont't you see?' Hermione breathed. 'If she could have done
one thing to make absolutely sure that every single person in this
school will read your interview, it was banning it!'
---'Harry Potter and the order of the phoenix', P513
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