【简答题】如图,在Rt△ABC中,∠C=90°,点P为AC边上的一点,将线段AP绕点A顺时针方向旋转(点P对应点P′),当AP旋转至AP′⊥AB时,点B、P、P′恰好在同一直线上,此时作P′E⊥AC于点E. (1)求证:∠CBP=∠ABP; (2)求证:AE=CP; (3)当 ,BP′= 时,求线段AB的长.
【简答题】P为线段AB中点时,(ABP)为( )。
【简答题】Only after I had reached the airport __________that I had forgotten to take my ticket with me. A) I realized B) have I realized C) did I realize D) I had realized
【单选题】如图,AB为等腰直角△ABC的斜边(AB为定长线段),O为AB的中点,P为AC延长线上的一 个动点,线段PB的垂直平分线交线段OC于点E,D为垂足,当P点运动时,给出下列四个结论: ①E为△ABP的外心; ②△PBE为等腰直角三角形; ③PC·OA = OE·PB; ④ CE + PC的值不变.
【简答题】I seem to have reached a rather gloomy conclusion, but I think that something cheerful may still be derived ________ it. A) of B) off C) from D) with