BOOKKU DDOONG - SHY DDOONG (feat. RAVI) - Single
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Bad Boyfriend & Jaime Deraz - On My Mind - Single
Jaime Deraz & Bad Boyfriend - In & Out - Single
Bad Boyfriend & Jaime Deraz - Rewind - Single
Dylan - Nineteen - Single
Julia Viktoria - Complicated - Single

[心]#为生命呐喊# [心]#因微爱聚合爱#Kindness is sometimes a knife, because the sharp edge is inward, so it is not others but oneself that hurt. Blind kindness equals sin. Social world is black and white. Only when you are strong can others understand your kindness. Therefore, before being strong, please be reasonable and kind.

【压轴题打卡434：圆有关的几何综合问题】
已知：A、B、C不在同一直线上.
（1）若点A、B、C均在半径为R的⊙O上，
i）如图一，当∠A=45°时，R=1，求∠BOC的度数和BC的长度；
ii）如图二，当∠A为锐角时，求证sin∠A=BC/2R；
（2）.若定长线段BC的两个端点分别在∠MAN的两边AM、AN（B、C均与点A不重合）滑动，如图三，当∠MAN=60°，BC=2时，分别作BP⊥AM，CP⊥AN，交点为点P ，试探索：在整个滑动过程中，P、A两点的距离是否保持不变？请说明理由.

#学科大挑战# #在微博过暑假#