As shown in Fig.3, AB=6, BC=8, CA=10. Point P is inside of the triangle ABC. DE, FG, and IH all pass point P and are parallel to AB, BC, and CA, respectively. The lengths of DE, FG and IH are all equal to d,then d= ___.(英汉小词典:parallel平行)
若等差数列{an}的公差为d,且a9-a4=2a3,am+an=2a5,则2aman/3a1d的最大值是___.
若关于x的不等式2kx2>(x-2)2恰有4个整数解,则实数k的取值范围是___.
若函数f(x)=(a+2)x2-ax+(2a-1)的两个零点分别在区间(-2,-1)和区间(0,1)内,则a的取值范围是___.
如图1,三棱锥A-BCD的顶点B、C、D在平面α内,CA=AB=BC=CD=DB=2,AD=6.若将该三棱锥以BC为轴转动,到点A落到平面α内为止,则
A、D两点所经过的路程之和是___.
如图2所示,已知AB切☉O于点B,直线AC交☉O于点C和D,若AD=DC,BC=2,则BD=___.